Saturday, November 09, 2019

But the humidity...

My mom just texted me to let me know that right now Patrick, in Missouri, is the coldest at 32°F. We're next here in Georgia at 40°F (though we are under a freeze warning so it might dip a little bit more). David in BC is at 41°F. Abra in Alberta is at 42°F. And those Utah people are at toasty 43°F.

But, you're likely saying to yourself, the humidity!

I hear this a lot and it drives me somewhat crazy. "It's a wet cold; it cuts right through your jacket!" or "It's a dry heat so it's not so bad."

Does humidity affect how we feel temperatures? Absolutely, but that isn't to say that any cold, humid temperature feels colder than any cold, dry temperature. As an example, a certain southerner I was talking with mentioned going outside—in the mountains, in Alberta, in December, wearing swim trunks, dripping wet—but that they "didn't feel the cold" because they're from Georgia and they're so used to a "humid cold" that the "dry cold" didn't bother them in the slightest.


Here's why: scientists already calculate the "feels like" temperature for us, factoring in things like wind chill or and the heat index (which, like the humidex in Canada, considers humidity).

Currently, my location is 36°F and it feels like 36°F. Up in Prince George, on the other hand, it's 43°F but the feels like temperature is only 40°F so they must be experiencing some wind chill.

Last year the coldest day in Atlanta was 13°F. This year, so far, the coldest day in Prince George was -27°F. And, in fact, they had an average high of only 10°F in February while in Atlanta our average high in February is...between 50 and 60°F).

Comparatively speaking, we're balmly down here (typically, though not today). It's true that being cold-and-wet makes you feel colder, but that's factored into the "feels like" temperature. When it's 40°F here—which is pretty cold for these parts—we feel chilly, but our kids still run around outside in bare feet...

When it's -39°F in Alberta (I'm looking at you, 1997)—which is pretty cold for those parts—children typically don't run around with bare feet (for hours) because...they would die. I'm just saying.

Humidity be darned: 40°F never feels colder than -40°F.

No amount of humidity is going to make those temperatures feel comparable (also because with colder weather, wind chill seems to be more of a factor in the "feels like" temperature than humidity is, if I'm reading things correctly).

So you can stop feeling poorly for me because we have a "wet cold" that cuts through our clothes and makes us feel like we'll never feel warm ever again because, well, I remember what it feels like to have snot freeze inside my nose. I remember wearing long johns under my jeans because I hated the feeling of my jeans freezing. I remember being, oh, so very cold, much colder than I've ever felt here (in the south at large, not specifically in Georgia).

I wonder, though, when people up north—where it gets legitimately cold—offer their condolences on our "humid cold" if they're simply underdressed for the winter where they are. For example, my brother mentioned that he had never felt colder than the cold he felt in his winters in England. Did he feel cold? Oh, sure. I don't doubt it. And I've felt cold down here as well. But I honestly think that's because I decide to wear flip-flops because I don't want to dig out my shoes (we're not even talking winter boots here; just shoes) or I decide I don't want to go through the trouble to get out our box of winter stuff (that we haven't even cracked open yet) to find our coats so we'll just make do with our sweaters.

Because, we know it's going to be 60°F again tomorrow (and if not tomorrow, then next week).

Whereas, in places that are truly cold, people tend to dress a little more appropriately for cold weather.

Now, as far as humidity goes in the heat, you can feel poorly for us then because it's true that when it's humid the heat index rises—it feels hotter. This doesn't mean that it doesn't feel hot in dry places, however. Like, I once saw a YouTuber suggest that there's a magical place where you can exercise all day in the hot sun without sweating or stinking—and the magical place was Utah!

And I was like, Wait. I lived in Utah. And I distinctly remember sweating there (and needing to shower and wear deodorant).

It is true that sweat is going to evaporate more quickly from your skin in a hot, dry environment. This will make you feel moderately cooler and, honestly, I don't think I've ever been hotter than that one day in Dubai—where it was hot and humid. But, I've also felt hot in Utah and Arizona and Jordan, so... I don't know what to tell you.

We had our hottest day of the year here on August 13. It was 100°F, with 39% humidity, making the heat index 108.5°F. Meanwhile, in Phoenix, the hottest day this year was July 16. They came in at a whopping 115°F, but with only 7% humidity, the actual "feels like" temperature would have been 107.5°F. 

So, it's true that the temperature felt cooler than it was in Arizona...but the difference is so negligible that we—or at least I—can confidently say that both places were pretty hot on their hottest day of the year. I mean, 107, 108—what's the difference?

The lows for those days, in case you're wondering were 83°F in Atlanta with 73% humidity, bringing their low "feels like" temperature at 88°F. The low in Phoenix was 96°F with 22% humidity, ultimately feeling like 93°F. Still both pretty warm, but with Phoenix beating out Atlanta—in spite of all that humidity (you can check my numbers here).

The long and short of this is, humidity does affect temperatures—mostly when we're talking about heat—but places that aren't very humid also can feel hot to humans. Humidity affects cold temperatures less (I think because as temperatures lower the air is less able to hold moisture, but don't quote me on that (seriously don't because it turns out that's a myth)) than warm temperatures, while wind chill has a greater effect on cold temperatures than on hot temperatures (hot wind whipping through the desert feels like being hit with a hair dryer).

So, that was a rant that no one needed, but I wanted to do the research anyway because I come from a line of people who enjoyed talking about the weather. My mom was a farmer's daughter and—now I'm going to tell the story wrong, but—her grandmother had a thermometer outside her bathroom window so when she needed to go to the bathroom she would say that she just needed to "check the temperature" but then she started saying that whenever she needed to use the bathroom. My mom's family did not have a thermometer outside their bathroom window (did they have a bathroom window?) but their Grandma would still "check the temperature" in there.

My family is always checking the weather and talking about it a lot.

And, actually, we have a bathroom window in one of our bathrooms and I've been tempted to get a thermometer to post outside so that we can check it...

(Upcoming rant: eye colour is not a strictly mendelian trait and therefore it is possible for two blue-eyed people to produce a brown-eyed baby. Or I will save myself some time and y'all can read this perfectly sound explanation here. I know my children were wondering about this).


  1. Yup, you got the temperature story wrong. We were the ones with a thermometer outside our bathroom window, and it was because of our thermometer that my grandma would say "I have the check the temperature" and then go to the bathroom.She did always tell us the temperature, but she would be in the bathroom for awhile, so... Because of that, our family began to use "checking the temperature" as a euphemism for needing the bathroom. I would like to point out that we also had a thermometer outside the kitchen window, so if Grandma actually needed to check the temperature that one would have worked, too. That said, the west side of the house (kitchen) got a lot more sun than the north side of the house (bathroom), so that made for an interesting temperature comparison, since the two thermometers often disagreed.

  2. See, and even I got it wrong. Got my east and west mixed up! For the sake of accuracy, the kitchen was on the east side of the house.

  3. Interesting post! I'm not sure I've heard too much talk about humidity and COLD since we are all about humidity and HEAT in these parts, but I do occasionally hear a bit about "damp cold" when it's cold and rainy. I like weather stuff so thanks for sharing your findings.

    Now I am off to read about the brown/blue eyed stuff because I was totally thinking about this not very many days ago because Zach. :)

    I enjoy learning from you!

  4. 12 years in the humidity and the only thing I miss is not having to use lotion but that was negated by my curly hair craziness. The humidity was not my friend. Sure 120 is worse then 100 or -29 is worse then 49 but if I have to have 100 with humidity or no humidity I choose none and if I have to have 32 dry and sunny or 32 rainy and cloudy, I take dry 😂

  5. Haha, this post makes me laugh! You are so right! BTW, in February Andy and I were in Australia when an "Arctic poloar blast" or whatever they called it hit the midwest and it hit -65 with the windchill (which I agree, I always think that's cheating! And if I had been there for it I would know the actual temp) and our phones kept ringing for alerts, cancelled school, etc. But the funny thing was that Andy got an email that was really directed to the international grad students that said something like "School is cancelled because of the extreme cold. This does not mean that you should go outside and play in the snow--stay inside or you will die" Something like that.

    So yeah, bit of a difference! :)