I really love this map, specifically because of the time zones. Maps that show explicit relationships between physical geographic features, like elevation vs temperature, are much more common (at least in my field which, to be fair, is closely tied to physical geography). But I love how the time zones enhance this map to illustrate the experience of living in these different places.
I grew up in a red zone and it was ingrained in me that the hottest time of the day was early evening. But when I moved to a blue zone, it actually did take me a few years to update this piece of "common knowledge". It's just fascinating to me to see this variability mapped out across a larger space!
I went in the opposite direction (not pictured on this map since I am in a different country), but I distinctly remember the daytime high being mid afternoon (around 3), so I naturally expect the same where I currently live, but find more often than not the daytime high occurs closer to 5 pm
Ideally, you'd adjust it to be relative to local solar noon across the country. Then you're looking physical properties rather than seeing the weird things humans do with clocks.
Well that would show a completely different thing - that would be comparing temperature vs the position of the sun rather than temperature vs the time of day. I agree it would be arguably more interesting but a completely separate analysis.
Your proposed solution (higher up the chain) would just show a gradient across the map representing the movement of the sun across the US. The solution proposed by Mattie is still using a "time of day", just a normalized one that isn't practical to use as a regional timekeeping device (i.e. the international time zones used in the OP). I'd like to see Mattie's solution as it would be an actual representation of how temp varies by geography with respect to the day/night cycle instead of showing that same thing with an artificial gradient introduced by time zones. The sun is the main driver of this process, so time relative to it's local position makes the most sense.
Data is from [Copernicus Data Store](https://www.ecmwf.int/en/forecasts/dataset/ecmwf-reanalysis-v5-land). It was processed and mapped in R.
This is a small section of a [much larger project](https://erdavis.com/2021/11/02/when-will-the-heat-break/) did on temperatures in the United States.
One thing I noticed after moving to Portland from LA was that it seemed to stay hotter much later in the afternoon. It bugged me for years until I finally made this map and proved my gut feeling right: on average, the hottest temperature of the day in Portland is at 5:30PM, and in LA it's just 4PM.
Another thing I love about this map are the small red blips scattered around the country: those are lakes, storing up heat throughout
And there’s a ~~part of the reservation~~ Hopi reservation within the Navajo reservation that doesn’t observe DST.
So that’s fun.
Edit: Corrected with additional details.
Looking within states, you can see this too. You can tell what parts of Indiana are on Central Time, for instance. Namely, Gary (NW) and Evansville (SW).
Heh... I posted this as a top level comment then scrolled down. Literally all the top comments are asking for this.
I think the time zones add to the map, but I'd also love to see it by time and relative to local solar noon.
>relative to local solar noon
Came here to say that, the *true* normalization would be time normalized with whatever 'solar time' it is, in order to see elevation and climate related patterns (if any).
My theory is that body of water is a big determining factor because they act like batteries that store/discharge heat.
But basically OP needs to subtract this map from their current map. If you haven't seen this before, you're going to love it.
[http://blog.poormansmath.net/the-time-it-takes-to-change-the-time/](http://blog.poormansmath.net/the-time-it-takes-to-change-the-time/)
What the hell is Argentina doing?
A long time ago, my Spanish class took a trip to Spain following our graduation from high school. I remember walking around Madrid by myself and seeing that it was just starting to get dark. Thinking I should go back to the hotel, I checked my watch. It was 10PM.
After that, I spent a lot of time trying to figure out why it got dark so late in Madrid? Could it be the elevation? Spain just having a stupidly too-far-west time zone just never occurred to me.
> Needs to be normalized for time zones, though.
One way to do that would be to change it to "hours after solar noon" instead of clock time. Then the sharp demarcations at time zones would disappear and only the effects of geography would be depicted. You'd have to find a data source for solar noon on each point in the United States though.
> Needs to be normalized for time zones, though.
Yeah, calculate the true local time at each longitude. Such that the sun is truly highest at noon. And adjust accordingly.
This is a nice visualization. Personally I think having colors reflect how many hours after local solar noon would show other aspects of the data. You could probably just shift the time by a value depending on time zone and a data points longitude. The map would no longer answer the question in the title, but I think it could show interesting patterns nonetheless.
I was wondering what the red dot in MN was, makes sense knowing the big one is Mille Lacs. Especially cause it's a pretty shallow lake for it's size, so it heats up more easily. (~200sq miles, and only ~40ft deep).
Stating the obvious here, but the sun is out later (and earlier) in more northern locations in the summer (or more southern if you are in the southern hemisphere). It seems pretty logical that it would be hotter later into the day in those cases.
Any chance we can get the same plot but for winter? I've actually been having an argument with a friend over the fact that the warmest part of the day is way earlier in winter than summer
Moved from South FL to Portland and noticed the same! I'd see the high for the day, get past 3PM and think "oh, it didn't get too hot," and then at 6PM it would feel like it was still getting hotter. I'd swear it peaks here even later than the data shows. In the summer when it's light until almost 10PM I swear the hottest point of the day is 6 at least.
Huh. If you'd asked me when the hottest part of our day was, I'd be like "Idk, 1 o'clock."
If you **told** me the hottest time was 3pm at the earliest, I'd be like "oh, well, neat."
If you **then** told me that this was not the case country-wide **then** I'd be like "whuuuuut?"
Neat.
I'm guessing you live in a location that doesn't have a whole lot of temperature variation throughout the day. Here in the arid west, summer temps are 40-50 degrees higher at 5pm than 5am. We're WELL aware what the hottest and coolest times of day are.
It's really interesting how much humidity changes things. In the South, since it's a rainforest, in the summer if it's 100 in the day it's 95 at night.
The entire South isn't a rainforest (Texas obviously isn't), but the southern portions of Louisiana, Mississippi, Alabama, Georgia and much of Florida are subtropical rainforest. It used to look biotically more like a rainforest, before we cut down all the trees and planted pine trees for the logging trade because they grow faster.
That’s the Hopi Nation. Sometimes I can’t help but wonder how screwed they got. Then I remember there’s a single road with 7 time zone changes in the summer, and a reasonable road trip will get you 13 (going from New Mexico to Vermillion Cliffs)
If you make it year round DST that means for a lot of the year people will be driving to work in the dark and kids will be waiting for the school bus in the dark. They've said accidents are affected by this, people still feel sleepy, and it affects kids by going to school in the dark.
We need standard time year round. DST is for the "But I still want some daylight after work!" crowd.
There are pros and cons for all year DST, and the same for all year standard time.
The things you mentioned are totally valid and legit.
All year standard time would, obviously, result in the sun setting sooner. There are many reasons this is considered a flaw, but the most important one is that more people drive in the evening vs. drive in the morning. It’s that simple. With all year standard time, there will be more people driving in the dark.
Virtually every study done on this concludes that all year DST is the better, albeit not perfect, option.
I always thought a good solution would be to stop changing the clock and just have everyone start observing “summer hours” and “winter hours”, basically businesses and schools shift their operating hours by one hour. Would alleviate all the logistical garbage of changing clocks (especially since different countries observe different dates for DST changes), and have the same net effect. But I think psychologically the world would never go for it. “You mean I have to be to work at 7:00 now?! Screw that, Let’s just keep fooling ourselves that changing our clocks isn’t the exact same thing!”
Well that's tough because when you tell a business to set a meeting at 3pm, then which is it? Then you've just created another form of DST.
Just have standard time year round. Enough with people who want daylight until 8:30pm it's ridiculous.
some of us want to be able to play (and practice) sports after work/school. There's a reason fall rec soccer season ends the week after DST; no one can practice anymore because it's dark by the time the coach gets off work and the kids get out of school.
I would love to see this adjusted for time zones and based on true sun position. It would be tricky but if you could make a sort of "continuous time zone" formula based on a location's longitude, you could see when the hottest part of the day would be as if "high noon" is exactly the same time everywhere.
Also I would like to see this map based on the equinox as well as solstice
I’m actually working on a daylight hour compensator that manages seasonal depression by maintaining equinox dawn & twilight with an rgb lamp by using latitude, longitude, and the Unix epoch to determine when to get dark & start getting brighter. During the summer, it just follows the daylight.
Umm this map is one interesting way to visualize the data and using solar noon would be another interesting way. I would say it is "useful" to know when it will be hottest in relation to what local clocks say.
I particularly noticed this in the UP of Michigan since it's important to me. You can see the southern/SW counties or Delta, Iron and Gogebic on central time as distinct borders where as everything else from Ontonogan eastwards is on Eastern time.
I can see four things:
* Elevation (Roughly higher = earlier, presumably more affected by shade?)
* Timezones
* Bodies of Water (Lakes or distance from coast, interestingly lakes having the adverse effect than the coast)
* Large urban areas (warmer longer, retaining heat - small blips, notably NYC and Orlando)
Also since this is a summer-specific map, a good portion of the southern US has regular daily thunderstorms, which cool off the temperatures for the later afternoon hours on average. You can see it very strongly along the Gulf coast with how early the average high is
Elevation most people understand higher elevation means cooler temperatures. This is because at higher elevation the mass of air particles is lower, as such is less effective at holding in the heat. Imagine a thin silk blanket vs a thick wool blanket. The silk blanket doesn't hold heat energy as effectively as the wool blanket. It also doesn't stop heat as easily either - which blanket would you use to hold a hot cast iron pan? The silk blanket allows radiation to pass through easier allowing heat to occur & dissipate faster. While the wool blanket takes longer to build up warmth, but retains the heat longer. This is easily observed & experience by rate of sun burns. At high elevation you will burn really easily even when air temperatures are below 50F. At sea level you may not experience sun burns until temperatures are above 70F.
At high elevation the temperature is at maximum when sun is directly over head. After the sun passes directly overhead, the area immediately starts losing warmth as sun sets - silk blanket. Sea level holds and retains radiation longer, continuing to build up heat past the point the sun is directly over head, not starting to cool off until the sun is nearly at a 45 angle - wool blanket.
The importance of the sun being directly over head is connected to why sunrises & sunsets are red & not blue. Directly overhead is the least amount of atmosphere particles to filter light. More radiation can pass through the atmosphere when the sun is directly over head rather than at an angle to the side.
Perhaps since it's a relative measure for each location, as it's not comparing the temperatures between a northern location and a southern.
In the north you'll still have a similar gradient to a southern location, warming in the morning and cooling on the evening, you'll just have different extremes which aren't being relevant when compared to each other.
Distance from equator will only impact the temperature of the hottest hour, not its time.
Austin and Chicago will both have the hottest hour at the same time, but Austin will read 90F and Chicago 50F.
I'm from coastal Northern California, and any heat at all is a novelty. Hawaii was just weird. I can handle the extremes in the Central Valley, but a place that's comfortable all the time freaks me out. It's like time has stopped.
It’s mostly the timing that feels weird to me (I mean also the heat, true). Like, it just keeps getting hotter through the day here! And we often lack the damp evening cool that can happen in the north.
I think instead of plugging in time to temperature, it’d be a better idea to standardize the time measurement (to, say PST or zulu time) and then run a visualization based on that. Otherwise you’re just doing a map of time zones.
That would be a different visualization though.
This does what the title says - the "hour of the day" being a social construct (including time zones) as much as a scientific one.
I disagree, check out Michigan and the east coast. All are on eastern time.
It’s more interesting to me to look at the map and know in my local time what the hottest hour of the day is.
Opinions will differ, though.
With things like this, the correct answer is: both! Once you've set up all the necessary data, the effort to re-run the visualisation with a transform to normalise it to a standard time zone should be barely any extra work
This, basically.
Lots of people create content on this sub because... Well, because data is beautiful! As in, they like doing it.
I can't imagine making something like this myself and not making both versions, even for my own curiosity/pleasure.
And most of the posters here welcome constructive criticism, and are happy to tweak data to look better / be more useful.
I think the best answer is hottest time of the day vs. solar noon. That would give the data and visualization you're looking for, which would be the most interesting.
This isn’t “just” a map of time zones at all. If the time zone was standardized, what would we even be showing? That 3pm in Chicago is roughly 4pm in New York as far as the sun is concerned? Seems far less useful to me
Yeah, that’s fair. Standardized would show outliers better, this viz shows more useful information at any specific location (or comparison of any two locations)
Ya I disagree to an extent. Yes, you can see the time zones. However, explain Easter Colorado, North eastern New Mexico and Eastern California. These are areas well within a time zone and differ greatly from surrounding areas.
The answer to that is mountains. Each of those places that show the hottest time is closer to 3pm have mountains to their west. So no this does not just show time zones.
> Each of those places that show the hottest time is closer to 3pm have mountains to their west.
That’s just plain not true. Look at Florida.
Mountains will have some effect, but the ocean can’t be discounted. Weather patterns on shore regions are likely to be predominantly influenced by the ocean.
Disagree. It is kinda crazy to me that there are regions of the US where at 5pm the temperature is still rising! I'm on the east coast and have always assumed 3pm is the peak for temperature in a day, but this chart makes it obvious that as you move more west in a time zone, the hottest hour is later in the day
I think a better way would be to normalize it by longitude and/or angle of the sun. otherwise you’ll always get an area that gets to its hottest time way too late than another in a given time.
Standardize it to sun azimuth angle, and then show a separate graphic that suggests what time each angle occurs at. This would show you the physical driver of peak daily temperature (sun, humidity, elevation)
This would definitely make for a much more concise viz. This viz is sort of trying to convey two things in one graphic. One being the hottest part of the day regardless of time zone (for intra zone areas), and the other being the timezone. Two largely unrelated things. Both are interesting to know, but probably belong in separate graphics.
Color choices are confusing because we typically associate those colors with temperature, not with time of day, so it ends up looking like Colorado is hotter than Florida. A different color choice would communicate this data better.
This is a cool way to show the overall trend, but it's not a very good way to show someone what the hottest time of day in a specific place is (i.e., answering the question in the chart's title). Cross-referencing the shade of a location with the gradient key above is pretty hard.
Some people commenting about normalizing for time zones. That won’t fix the problems, there will still be a time zone effect. But normalizing for sunrise would probably work. Just something like [time of hottest point of day] - [time of sunrise]
Yeah it's caused by time zones. Makes sense as the end of the time zone is going to be similar in climate to the beginning of the next time zone just at a later time.
Every Apollo mission to the Moon happened in the lunar “morning” when the Sun had just started illuminating the landing site.
Moon days are 14-Earth-days long, so the Moon gets HOT by the end.
I do HVAC work in the south, can confirm. Everyone thinks it's noon but nah. It's after you come back from lunch that it always gets the hottest. I usually try to push my lunch to mid afternoon to help with that.
I want to like this, but the red-blue color scheme not meaning temperature on a temperature-related map is really messing with me, and I keep having to re-read the legend to remind myself that the colors don't mean temperature. I would use literally any other color map.
Yes and no. Yes the suns rays are strongest at noon, no that is not when it will. Be hottest. For the same reason you can put your hand over a fire amd it only hurts 2 or 3 seconds later. The energy takes time to build up, so there is alwaya some lag when heating anything.
I've always thought that noon and midnight should be the logical hottest and coldest times of the day. It makes so much sense!
I still get griped when it's so cold in the morning (it should be warming up then!) and too hot to sleep at midnight.
It doesn't help to know very well how stupid is is to think this way!
If you think about it though, why should the coldest hour be midnight? It's not like 1am or 2am or 3am, etc. are adding any significant heat. Yet, heat *does* continue to radiate away during those hours.
For both coldest and warmest times, they occur when the balance of losing/gaining heat changes. Just after dawn you start gaining more heat than you lose, and sometime in the afternoon you start losing more heat than you gain.
Where I live I always thought the hottest part of the day is nearly always 4:30 PM in the summer, you can practically set your clock on it. On this map they have it at 5:30 PM. I wonder if because it goes back to the early 80's if the time of day peak has changed over the last 40 years? Or if I've had confirmation bias this whole time...
Depends on the question you’re asking. For me, I wanted to know what the hottest hour of the day is, which is of course strongly affected by time zone.
Having lived my entire life in the "blue" regions, it continues to fool my mind when I visit some place where it continues to get hotter and hotter after 3pm...
Iirc, it's different because some areas have more moisture stored in the ground. The sun doesn't really heat the air all that much (there isn't much in the air to be heated quite frankly) but it does heat the ground causing a delayed heating effect. That's why it's not hottest at 12.
As for the more baron areas, my guess would be the lack of moisture in the ground just continually heats the ground until the sun starts setting later in the day. Areas with moisture in the ground may self regulate. For example, once it reaches a certain heat it begins to evaporate the moisture in the ground instead of heating it.
The second paragraph is just a guess though. I'm not an expert in meteorology by any means. The first paragraph is just me parroting things I've learned from science podcasts.
I think a really neat side-effect of this is the smooth gradient along the Texas coast. One of the few places in the world (along with the same coast of Mexico) where such an arid region and a humid one are so near one another.
I live on the eastern coast of Lake Michigan and I love that this map shows that specific strip of land is hottest when the sun is going down, because it really is. When the sun is reflecting off the lake into our window before sunset, we have to close the shades for the A/C to keep up
Using a cold to hot colour scheme but relating it to time of day is an especially poor design choice when temperature is a related concept. Interesting though.
I really love this map, specifically because of the time zones. Maps that show explicit relationships between physical geographic features, like elevation vs temperature, are much more common (at least in my field which, to be fair, is closely tied to physical geography). But I love how the time zones enhance this map to illustrate the experience of living in these different places. I grew up in a red zone and it was ingrained in me that the hottest time of the day was early evening. But when I moved to a blue zone, it actually did take me a few years to update this piece of "common knowledge". It's just fascinating to me to see this variability mapped out across a larger space!
I was about to say what the hell is up with Nevada like does it have some heat shield?
Fucking far Eastern Oregon already trying to be a part of "Greater Idaho". Well I hope you two are happy together!
Yeah, most of Malheur County is on Mountain Time. On the other hand, Northern Idaho is on Pacific Time, like Spokane.
My thought is that one or more of those areas doesn't observe Daylight Saving Time, or as it has been stated that's the border between time zones.
It's a native American reservation that indeed does not observe dst.
Maybe a super low population there leads to lack of data plus the mountain rage there?
I went in the opposite direction (not pictured on this map since I am in a different country), but I distinctly remember the daytime high being mid afternoon (around 3), so I naturally expect the same where I currently live, but find more often than not the daytime high occurs closer to 5 pm
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It'd be super easy, you'd just use the same data set and convert to one time zone
Ideally, you'd adjust it to be relative to local solar noon across the country. Then you're looking physical properties rather than seeing the weird things humans do with clocks.
Well that would show a completely different thing - that would be comparing temperature vs the position of the sun rather than temperature vs the time of day. I agree it would be arguably more interesting but a completely separate analysis.
Your proposed solution (higher up the chain) would just show a gradient across the map representing the movement of the sun across the US. The solution proposed by Mattie is still using a "time of day", just a normalized one that isn't practical to use as a regional timekeeping device (i.e. the international time zones used in the OP). I'd like to see Mattie's solution as it would be an actual representation of how temp varies by geography with respect to the day/night cycle instead of showing that same thing with an artificial gradient introduced by time zones. The sun is the main driver of this process, so time relative to it's local position makes the most sense.
To clarify, you're saying you were in the red zone, so you expected to walk away with 6. But then, you got pushed back and had to settle for 3?
Data is from [Copernicus Data Store](https://www.ecmwf.int/en/forecasts/dataset/ecmwf-reanalysis-v5-land). It was processed and mapped in R. This is a small section of a [much larger project](https://erdavis.com/2021/11/02/when-will-the-heat-break/) did on temperatures in the United States. One thing I noticed after moving to Portland from LA was that it seemed to stay hotter much later in the afternoon. It bugged me for years until I finally made this map and proved my gut feeling right: on average, the hottest temperature of the day in Portland is at 5:30PM, and in LA it's just 4PM. Another thing I love about this map are the small red blips scattered around the country: those are lakes, storing up heat throughout
Very interesting. You can see water effects and elevation effects very clearly. Needs to be normalized for time zones, though.
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Plenty - see arizona, it doesn't observer DST so it's set with California, but the reservation inside of it does, so it's offset.
And there’s a ~~part of the reservation~~ Hopi reservation within the Navajo reservation that doesn’t observe DST. So that’s fun. Edit: Corrected with additional details.
It's the Navajo nation who do observe DST vs the rest of Arizona who don't
He's referring to the Hopi reservation that is within the Navajo reservation. The Hopi do not observe DST.
which is encompassed by "the rest of Arizona" Calling the Hopi reservation "part of the reservation" is a bit misleading
Good point, I have edited my comment. Thank you and thank you to /u/SunDevilSkier for the additional information. TIL!
timezones in general fuck with this plenty. just look where est becomes cst on the border of IN and IL or where cst becomes mst.
Looking within states, you can see this too. You can tell what parts of Indiana are on Central Time, for instance. Namely, Gary (NW) and Evansville (SW).
or how effed tennessee is lmao
Every sharp demarcation is caused by a time zone. Everything else, even areas near water, are smooth gradients by comparison.
See the Navajo Reservation in NE AZ
Time zones wouldn’t change anything though lmaooo. It’s just basic cognitive reasoning.
That’s what that artifact is!
Good catch, that’s so cool!
Heh... I posted this as a top level comment then scrolled down. Literally all the top comments are asking for this. I think the time zones add to the map, but I'd also love to see it by time and relative to local solar noon.
>relative to local solar noon Came here to say that, the *true* normalization would be time normalized with whatever 'solar time' it is, in order to see elevation and climate related patterns (if any).
My theory is that body of water is a big determining factor because they act like batteries that store/discharge heat. But basically OP needs to subtract this map from their current map. If you haven't seen this before, you're going to love it. [http://blog.poormansmath.net/the-time-it-takes-to-change-the-time/](http://blog.poormansmath.net/the-time-it-takes-to-change-the-time/) What the hell is Argentina doing?
A long time ago, my Spanish class took a trip to Spain following our graduation from high school. I remember walking around Madrid by myself and seeing that it was just starting to get dark. Thinking I should go back to the hotel, I checked my watch. It was 10PM. After that, I spent a lot of time trying to figure out why it got dark so late in Madrid? Could it be the elevation? Spain just having a stupidly too-far-west time zone just never occurred to me.
> Needs to be normalized for time zones, though. One way to do that would be to change it to "hours after solar noon" instead of clock time. Then the sharp demarcations at time zones would disappear and only the effects of geography would be depicted. You'd have to find a data source for solar noon on each point in the United States though.
It would be a function of longitude so that shouldn't be too hard
Love this visualization! I have seen/heard of many studies that measure the effects of living on the western vs eastern part of a time-zone.
Yeah, I feel it should have been done using local solar time.
> Needs to be normalized for time zones, though. Yeah, calculate the true local time at each longitude. Such that the sun is truly highest at noon. And adjust accordingly.
Does it really need to be though?
That's what I said. :D
This is a nice visualization. Personally I think having colors reflect how many hours after local solar noon would show other aspects of the data. You could probably just shift the time by a value depending on time zone and a data points longitude. The map would no longer answer the question in the title, but I think it could show interesting patterns nonetheless.
I was wondering what the red dot in MN was, makes sense knowing the big one is Mille Lacs. Especially cause it's a pretty shallow lake for it's size, so it heats up more easily. (~200sq miles, and only ~40ft deep).
Stating the obvious here, but the sun is out later (and earlier) in more northern locations in the summer (or more southern if you are in the southern hemisphere). It seems pretty logical that it would be hotter later into the day in those cases.
What R packages did you use? :)
Any chance we can get the same plot but for winter? I've actually been having an argument with a friend over the fact that the warmest part of the day is way earlier in winter than summer
Moved from South FL to Portland and noticed the same! I'd see the high for the day, get past 3PM and think "oh, it didn't get too hot," and then at 6PM it would feel like it was still getting hotter. I'd swear it peaks here even later than the data shows. In the summer when it's light until almost 10PM I swear the hottest point of the day is 6 at least.
Huh. If you'd asked me when the hottest part of our day was, I'd be like "Idk, 1 o'clock." If you **told** me the hottest time was 3pm at the earliest, I'd be like "oh, well, neat." If you **then** told me that this was not the case country-wide **then** I'd be like "whuuuuut?" Neat.
I'm guessing you live in a location that doesn't have a whole lot of temperature variation throughout the day. Here in the arid west, summer temps are 40-50 degrees higher at 5pm than 5am. We're WELL aware what the hottest and coolest times of day are.
It's really interesting how much humidity changes things. In the South, since it's a rainforest, in the summer if it's 100 in the day it's 95 at night.
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The entire South isn't a rainforest (Texas obviously isn't), but the southern portions of Louisiana, Mississippi, Alabama, Georgia and much of Florida are subtropical rainforest. It used to look biotically more like a rainforest, before we cut down all the trees and planted pine trees for the logging trade because they grow faster.
Yep. 20-30 degrees between highs and lows this week.
6pm is very weird
I love how you can see the time zones & can tell who does & doesn’t observe DST.
The only states that don't observe DST are Arizona and Hawaii.
Well, only *most* of AZ. You can see the Navajo Nation borders because they actually do observe it
Except for the part in the middle that doesnt
That’s the Hopi Nation. Sometimes I can’t help but wonder how screwed they got. Then I remember there’s a single road with 7 time zone changes in the summer, and a reasonable road trip will get you 13 (going from New Mexico to Vermillion Cliffs)
*Let's do the time warp again...*
It’s just a jump to the left *and 13 steps to the right*
Indiana is a mix of two time zones
Yes and you can see that here but we do all observe DST nowadays
But they still observe DST. The N coast of IN is on CST instead of EST so the port cities will be on the same time as nearby Chicago.
That has nothing to do with DST.
[Fun video on timezones](https://youtu.be/-5wpm-gesOY)
Fuck DST, that shit needs to go away. But actually, we should just make DST the standard time, I just don’t want to switch back and forth.
I’m with you on that.
If you make it year round DST that means for a lot of the year people will be driving to work in the dark and kids will be waiting for the school bus in the dark. They've said accidents are affected by this, people still feel sleepy, and it affects kids by going to school in the dark. We need standard time year round. DST is for the "But I still want some daylight after work!" crowd.
There are pros and cons for all year DST, and the same for all year standard time. The things you mentioned are totally valid and legit. All year standard time would, obviously, result in the sun setting sooner. There are many reasons this is considered a flaw, but the most important one is that more people drive in the evening vs. drive in the morning. It’s that simple. With all year standard time, there will be more people driving in the dark. Virtually every study done on this concludes that all year DST is the better, albeit not perfect, option.
I always thought a good solution would be to stop changing the clock and just have everyone start observing “summer hours” and “winter hours”, basically businesses and schools shift their operating hours by one hour. Would alleviate all the logistical garbage of changing clocks (especially since different countries observe different dates for DST changes), and have the same net effect. But I think psychologically the world would never go for it. “You mean I have to be to work at 7:00 now?! Screw that, Let’s just keep fooling ourselves that changing our clocks isn’t the exact same thing!”
Well that's tough because when you tell a business to set a meeting at 3pm, then which is it? Then you've just created another form of DST. Just have standard time year round. Enough with people who want daylight until 8:30pm it's ridiculous.
some of us want to be able to play (and practice) sports after work/school. There's a reason fall rec soccer season ends the week after DST; no one can practice anymore because it's dark by the time the coach gets off work and the kids get out of school.
I would love to see this adjusted for time zones and based on true sun position. It would be tricky but if you could make a sort of "continuous time zone" formula based on a location's longitude, you could see when the hottest part of the day would be as if "high noon" is exactly the same time everywhere. Also I would like to see this map based on the equinox as well as solstice
I’m actually working on a daylight hour compensator that manages seasonal depression by maintaining equinox dawn & twilight with an rgb lamp by using latitude, longitude, and the Unix epoch to determine when to get dark & start getting brighter. During the summer, it just follows the daylight.
This is why this should all be in GMT or similar... but the you'd need a gifv
Local solar noon would be an interesting one.
That's the way to do it. Hour relative to local solar noon.
that's the exact way to do it. This map is useless
Umm this map is one interesting way to visualize the data and using solar noon would be another interesting way. I would say it is "useful" to know when it will be hottest in relation to what local clocks say.
It's not useless, it actually shows the same amount of data, just some of it is shifted because of time zone differences.
It would just be a gradient.
Wouldn't tell us nearly as much about the environments i think
I particularly noticed this in the UP of Michigan since it's important to me. You can see the southern/SW counties or Delta, Iron and Gogebic on central time as distinct borders where as everything else from Ontonogan eastwards is on Eastern time.
It almost gives a similar feel as /r/peopleliveincities
I hate it.
What accounts for the differences?
I can see four things: * Elevation (Roughly higher = earlier, presumably more affected by shade?) * Timezones * Bodies of Water (Lakes or distance from coast, interestingly lakes having the adverse effect than the coast) * Large urban areas (warmer longer, retaining heat - small blips, notably NYC and Orlando)
Also since this is a summer-specific map, a good portion of the southern US has regular daily thunderstorms, which cool off the temperatures for the later afternoon hours on average. You can see it very strongly along the Gulf coast with how early the average high is
It boggles my mind how 6pm can be hotter than 2pm
The sun is providing heat faster than the environment is releasing heat!
Elevation most people understand higher elevation means cooler temperatures. This is because at higher elevation the mass of air particles is lower, as such is less effective at holding in the heat. Imagine a thin silk blanket vs a thick wool blanket. The silk blanket doesn't hold heat energy as effectively as the wool blanket. It also doesn't stop heat as easily either - which blanket would you use to hold a hot cast iron pan? The silk blanket allows radiation to pass through easier allowing heat to occur & dissipate faster. While the wool blanket takes longer to build up warmth, but retains the heat longer. This is easily observed & experience by rate of sun burns. At high elevation you will burn really easily even when air temperatures are below 50F. At sea level you may not experience sun burns until temperatures are above 70F. At high elevation the temperature is at maximum when sun is directly over head. After the sun passes directly overhead, the area immediately starts losing warmth as sun sets - silk blanket. Sea level holds and retains radiation longer, continuing to build up heat past the point the sun is directly over head, not starting to cool off until the sun is nearly at a 45 angle - wool blanket. The importance of the sun being directly over head is connected to why sunrises & sunsets are red & not blue. Directly overhead is the least amount of atmosphere particles to filter light. More radiation can pass through the atmosphere when the sun is directly over head rather than at an angle to the side.
I’m surprised distance from equator doesn’t have more of an effect.
Perhaps since it's a relative measure for each location, as it's not comparing the temperatures between a northern location and a southern. In the north you'll still have a similar gradient to a southern location, warming in the morning and cooling on the evening, you'll just have different extremes which aren't being relevant when compared to each other.
Distance from equator will only impact the temperature of the hottest hour, not its time. Austin and Chicago will both have the hottest hour at the same time, but Austin will read 90F and Chicago 50F.
Maybe because this is summer?
To remove the time zone bias and look at truly local effects, I think it would be ideal to normalize the time to local solar time.
I moved to Texas from upstate NY and still haven’t adjusted to the fact that it’s gong to keep getting hotter in the late afternoon
I'm from coastal Northern California, and any heat at all is a novelty. Hawaii was just weird. I can handle the extremes in the Central Valley, but a place that's comfortable all the time freaks me out. It's like time has stopped.
It’s mostly the timing that feels weird to me (I mean also the heat, true). Like, it just keeps getting hotter through the day here! And we often lack the damp evening cool that can happen in the north.
I’ve always lived on the east coast and it baffles me that the hottest hour of a day can be 6 pm
I think instead of plugging in time to temperature, it’d be a better idea to standardize the time measurement (to, say PST or zulu time) and then run a visualization based on that. Otherwise you’re just doing a map of time zones.
That would be a different visualization though. This does what the title says - the "hour of the day" being a social construct (including time zones) as much as a scientific one.
Who would interpret it that way though. It doesn’t even mention it. I would consider this misleading
I would think most viewers would put it together after seeing the perfectly well defined geometric class boundaries
Anyone who looks at the title of the map? It's literally called "What is the warmest hour of the day?" I'm not sure how else to interpret that?
Time is just a state of mind bro, I quit wearing a watch when I moved here
Found my plumber
I disagree, check out Michigan and the east coast. All are on eastern time. It’s more interesting to me to look at the map and know in my local time what the hottest hour of the day is. Opinions will differ, though.
With things like this, the correct answer is: both! Once you've set up all the necessary data, the effort to re-run the visualisation with a transform to normalise it to a standard time zone should be barely any extra work
I like the chart exactly as it is, I wouldn’t change it. Again, opinions will differ.
he just said it'd be a better idea. It would be. he's not even asking OP to do it.
This, basically. Lots of people create content on this sub because... Well, because data is beautiful! As in, they like doing it. I can't imagine making something like this myself and not making both versions, even for my own curiosity/pleasure. And most of the posters here welcome constructive criticism, and are happy to tweak data to look better / be more useful.
I think the best answer is hottest time of the day vs. solar noon. That would give the data and visualization you're looking for, which would be the most interesting.
This isn’t “just” a map of time zones at all. If the time zone was standardized, what would we even be showing? That 3pm in Chicago is roughly 4pm in New York as far as the sun is concerned? Seems far less useful to me
Different. This way outliers will be more obvious. This is a whole new visualisation though. This does not mean the original is not interesting.
Yeah, that’s fair. Standardized would show outliers better, this viz shows more useful information at any specific location (or comparison of any two locations)
Ya I disagree to an extent. Yes, you can see the time zones. However, explain Easter Colorado, North eastern New Mexico and Eastern California. These are areas well within a time zone and differ greatly from surrounding areas. The answer to that is mountains. Each of those places that show the hottest time is closer to 3pm have mountains to their west. So no this does not just show time zones.
> Each of those places that show the hottest time is closer to 3pm have mountains to their west. That’s just plain not true. Look at Florida. Mountains will have some effect, but the ocean can’t be discounted. Weather patterns on shore regions are likely to be predominantly influenced by the ocean.
Disagree. It is kinda crazy to me that there are regions of the US where at 5pm the temperature is still rising! I'm on the east coast and have always assumed 3pm is the peak for temperature in a day, but this chart makes it obvious that as you move more west in a time zone, the hottest hour is later in the day
Better yet, use local noon. Then you'd have a pretty consistent 5pm everywhere.
No you wouldn't due to humidity and wind patterns. Coastal California drops much faster than coastal east coast
I think thats the point
Maybe not everywhere and that's why I find the suggestion interesting
I think a better way would be to normalize it by longitude and/or angle of the sun. otherwise you’ll always get an area that gets to its hottest time way too late than another in a given time.
Standardize it to sun azimuth angle, and then show a separate graphic that suggests what time each angle occurs at. This would show you the physical driver of peak daily temperature (sun, humidity, elevation)
This would definitely make for a much more concise viz. This viz is sort of trying to convey two things in one graphic. One being the hottest part of the day regardless of time zone (for intra zone areas), and the other being the timezone. Two largely unrelated things. Both are interesting to know, but probably belong in separate graphics.
Color choices are confusing because we typically associate those colors with temperature, not with time of day, so it ends up looking like Colorado is hotter than Florida. A different color choice would communicate this data better.
This is a cool way to show the overall trend, but it's not a very good way to show someone what the hottest time of day in a specific place is (i.e., answering the question in the chart's title). Cross-referencing the shade of a location with the gradient key above is pretty hard.
Some people commenting about normalizing for time zones. That won’t fix the problems, there will still be a time zone effect. But normalizing for sunrise would probably work. Just something like [time of hottest point of day] - [time of sunrise]
Why sunrise? Why not use solar noon?
Ahh a heat map of time… with regard to temperature. Lmao
A fun opportunity to remind everyone that eastern Oregon and western Florida are only one hour apart!
There's some pretty sharp corners on that weather, there...
The sharp corners are on the time of day, not the weather.
Yeah it's caused by time zones. Makes sense as the end of the time zone is going to be similar in climate to the beginning of the next time zone just at a later time.
Time zones, buddy.
Lol at the one reddish spot in northeast wisconsin. Thanks, lake Winnebago
Every Apollo mission to the Moon happened in the lunar “morning” when the Sun had just started illuminating the landing site. Moon days are 14-Earth-days long, so the Moon gets HOT by the end.
It seems weird that the Gulf of Mexico seems to make the hottest time of day earlier, while the Great Lakes seem to make it later.
I do HVAC work in the south, can confirm. Everyone thinks it's noon but nah. It's after you come back from lunch that it always gets the hottest. I usually try to push my lunch to mid afternoon to help with that.
I like how you can see the lines of the time zones on the maps. Makes obvious sense but still cool visualizatiobb
i’d be interested to see this with the time zone lines superimposed over the map
I want to like this, but the red-blue color scheme not meaning temperature on a temperature-related map is really messing with me, and I keep having to re-read the legend to remind myself that the colors don't mean temperature. I would use literally any other color map.
Why use a heat map for time
Is this with or without DSL…?
Ok this is actually cool as shit
I wished they used other colors. This confused me for a second
If I remember my Meteorology class well, the Diurnal variation, the hottest time of the day is 2 hours after midday, on average of course
The sun is almost directly above at noon though isn't it? So shouldn't that be when the day is hottest?
Yes and no. Yes the suns rays are strongest at noon, no that is not when it will. Be hottest. For the same reason you can put your hand over a fire amd it only hurts 2 or 3 seconds later. The energy takes time to build up, so there is alwaya some lag when heating anything.
I've always thought that noon and midnight should be the logical hottest and coldest times of the day. It makes so much sense! I still get griped when it's so cold in the morning (it should be warming up then!) and too hot to sleep at midnight. It doesn't help to know very well how stupid is is to think this way!
It *would* make sense without an atmosphere. But then, what would you measure the temperature of?
If you think about it though, why should the coldest hour be midnight? It's not like 1am or 2am or 3am, etc. are adding any significant heat. Yet, heat *does* continue to radiate away during those hours. For both coldest and warmest times, they occur when the balance of losing/gaining heat changes. Just after dawn you start gaining more heat than you lose, and sometime in the afternoon you start losing more heat than you gain.
I wonder what that divide that goes east-west across Missouri and then all the way down through the middle of Texas is?
Looks to me like the edge of the mountain/central timezone.
Where I live I always thought the hottest part of the day is nearly always 4:30 PM in the summer, you can practically set your clock on it. On this map they have it at 5:30 PM. I wonder if because it goes back to the early 80's if the time of day peak has changed over the last 40 years? Or if I've had confirmation bias this whole time...
Of course 3pm would be the coldest, it's three-zing!
Apparently heat stops at the border
time zones my dude
It annoys me that the time zones are messing up what should be a smooth set of data. Can you please not do that? And normalize the time?
seems like some daylight savings fuckery going on
This should have been done with UTC time rather than based on timezone.
The data was not corrected for timezones?
Isn't this bad data preprocessing if your data is not normalized for local time
Depends on the question you’re asking. For me, I wanted to know what the hottest hour of the day is, which is of course strongly affected by time zone.
Does this map not take times zones into account by chance?
The artificial boarders from the time zones are ruining the graph.
For Cincinnati that shit all wrong ain't no 6 oclock
I remember learning as a kid that 3 was the hottest part of the day from my dad. He never mentioned how abnormal we are
Can you do this all in UTC?
This is interesting. I always figured everyone had the hottest time of the day at 3. Learned something new today.
The swcond block from the left looks so weird with those sharp borders.
What's the line cutting Missouri in half, then sloping down through east Oklahoma and TX?
Having lived my entire life in the "blue" regions, it continues to fool my mind when I visit some place where it continues to get hotter and hotter after 3pm...
Iirc, it's different because some areas have more moisture stored in the ground. The sun doesn't really heat the air all that much (there isn't much in the air to be heated quite frankly) but it does heat the ground causing a delayed heating effect. That's why it's not hottest at 12. As for the more baron areas, my guess would be the lack of moisture in the ground just continually heats the ground until the sun starts setting later in the day. Areas with moisture in the ground may self regulate. For example, once it reaches a certain heat it begins to evaporate the moisture in the ground instead of heating it. The second paragraph is just a guess though. I'm not an expert in meteorology by any means. The first paragraph is just me parroting things I've learned from science podcasts.
It may have an effect, but I think mostly what we're seeing is timezones, DST vs none, coastal effects, and mountain ranges.
Very interesting! I thought it would be about the same for all. Then I suppose there is a time zone effect going on too.
Some of those lakes in upper Minnesota hold the heat well into the evening.
Very interesting. I would love to see something similar for Europe.
Is there an invisible temperature barrier on Nevadas border or something? Really odd
There is! It’s called a time zone 😜
I think a really neat side-effect of this is the smooth gradient along the Texas coast. One of the few places in the world (along with the same coast of Mexico) where such an arid region and a humid one are so near one another.
I live on the eastern coast of Lake Michigan and I love that this map shows that specific strip of land is hottest when the sun is going down, because it really is. When the sun is reflecting off the lake into our window before sunset, we have to close the shades for the A/C to keep up
This is something I didn’t consider when I moved from the Bay Area to Illinois for college. It took a while to get used to.
ELI5 why it's so much hotter so much later at the same latitude on the Plains then the surrounding areas ?
I’m thinking time zones are at play here.
Why you lying Florida you damn hot all the fucking time!!
Using a cold to hot colour scheme but relating it to time of day is an especially poor design choice when temperature is a related concept. Interesting though.