Dry heat vs humid heat

Travis

Misanthrope of the Mountains
Travis
Joined
Mar 31, 2007
Messages
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I live in California. And each summer we will get a few bad heatwaves. While I'm sweltering under 115F (46C) conditions I'll suddenly have someone on the internet tell me that "at least it is a dry heat!" Which sort of makes me want to punch the wall. Which I won't do....of course because of the heat that I apparently shouldn't even notice. :rolleyes:

So....dry heat vs humid heat.

DRY HEAT|HUMID HEAT
Easy to dehydrate|Easy to get heat stroke

Which is truly worse?
 
Dehydration is prevented by greater fluid intake.
Heat stroke is prevented by not being hot.

You can control how much water you drink more easily than the current temperature. Most people don't have AC.

Having been in both 110°/1% and 90°/99% humidity conditions, my experience says dry heat is much easier to withstand. Though, neither was much fun for my temperate-climate-loving body.
 
GodMark2 said:
Dehydration is prevented by greater fluid intake.
Heat stroke is prevented by not being hot.

You can control how much water you drink more easily than the current temperature. Most people don't have AC.

Having been in both 110°/1% and 90°/99% humidity conditions, my experience says dry heat is much easier to withstand. Though, neither was much fun for my temperate-climate-loving body.
Click to expand...

Never been to Arizona, huh? ;)

I am certainly more comfortable with the dry heat. But 115 is hot no matter what. At least when it gets that hot your body can evaporate enough to lower your body temp.

ETA: Here's the wiki entry on Heat Index. Unfortunately, it doesn't really deal with the situation Travis describes (at least in the chart).

http://www.youtube.com/watch?v=gA0GcXV2njY
 
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Travis said:
I live in California. And each summer we will get a few bad heatwaves. While I'm sweltering under 115F (46C) conditions I'll suddenly have someone on the internet tell me that "at least it is a dry heat!" Which sort of makes me want to punch the wall. Which I won't do....of course because of the heat that I apparently shouldn't even notice. :rolleyes:

So....dry heat vs humid heat.

DRY HEAT|HUMID HEAT
Easy to dehydrate|Easy to get heat stroke

Which is truly worse?
Click to expand...

Yeah? Well, why don't you come over to New York, my man? So you can experience what a living HELL humid heat is. You feel like you're in a *********** sauna. You feel like you can't breathe. You feel like you're choking. You feel sticky all over your body, like the heat is a physical entity covering all of your body. How's Humid heat sounding now? Still interested?

I second your friend's opinion. Humidity is a factor alone that makes any temperature feel three times worse than it actually is. The first time I was at Vegas, it was hot as Hell... but it was dry. It felt so nice to experience dry heat. The first time I went to Paris, they told me it was like minus two degrees. But since it was dry, it was nothing compared to the humid cold in New York. Therefore, dry anything is better than humid anything, when it comes to weather.

Obviously, any extreme is bad, and both dehydration and strokes are bad things. But in terms of "how it feels", I think the sensation of Humid Heat is particularly horrible.
 
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I've never been experience dry heat enough to judge, but from a lifetime of Houston summers, I can say that humid heats sucks.
 
In a dry heat the moisture on your skin from perspiration can evaporate and cool you. In a wet heat it cannot.

Google "wet bulb temperature" for more technical details. In short, the body will overheat faster in wet heat than in dry heat of the same temperature.
 
In dry heat your sweat evaporates and cools you somewhat. In humid heat there's less evaporation, thus less cooling.

I've experienced both 116F with dewpoints in the teens or lower and 116F with dewpoints in the sixties. The drier heat is much easier to tolerate.

Also, around here (Phoenix Metro Area) temperatures of 110+ are dangerous, but you don't usually see a lot of people dying (unless they do something stupid like go hiking) because the dewpoints are usually low when it's that hot. The one summer where we had 110+ temps plus high dewpoints it was like a heat wave back East -- people were dropping like flies.
 
I'll definitely say I think humid heat is worse. Dry heat is both less unpleasant and easier to combat. When I lived on the edge of the Mojave desert, I would routinely just hop in the shower with all my clothes on before going outside. It provided quite effective cooling. In a New York summer, that would just make you wet as well as hot.

Of course, not all of California is as dry as the Mojave. Humidity on the coast is going to be much higher. So you may want to be cautious if you experiment.
 
I've experienced both in the past two months.
I prefer dry heat. Unfortunately, I live in humid heat.
 
Travis said:
So....dry heat vs humid heat.

DRY HEAT|HUMID HEAT
Easy to dehydrate|Easy to get heat stroke

Which is truly worse?
Click to expand...

With dry heat, your sweat helps cool you by easier evaporation.

But obviously, there are limits. At the same temperature, with the same amount (or lack) of wind, I'd prefer dry heat. But the implication usually is that a person would rather take higher temperature for less humidity. The limit of that trade off is obvious in the heat index.
 
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Humid heat by far. It can get to a dry 47C in Melbourne, but this is far more comfortable than 35C in North Queensland.
 
I'm sorry, reality disagrees

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5529a2.htm

During 1999--2003, a total of 3,442 deaths resulting from exposure to extreme heat were reported (annual mean: 688). For 2,239 (65%) of these deaths, the underlying cause of death was recorded as exposure to excessive heat; for the remaining 1,203 (35%), hyperthermia was recorded as a contributing factor. Deaths among males accounted for 66% of deaths and outnumbered deaths among females in all age groups (Figure). Of the 3,401 decedents for whom age information was available, 228 (7%) were aged <15 years, 1,810 (53%) were aged 15--64 years, and 1,363 (40%) were aged >65 years. The state with the highest average annual hyperthermia-related death rate during 1999--2003 was Arizona (1.7 deaths per 100,000 population), followed by Nevada (0.8) and Missouri (0.6).
Click to expand...
 
Dry heat.

I live near Seattle which, in spite of its reputation, gets hot sometimes but rarely gets hot with an uncomfortable heat index. Sure, it gets hot and muggy once in a while, but I hadn't experienced real humidity till I visited Ohio in July.

It felt like getting mugged by a wool blanket soaked in hot water. It took an effort to get a breath of air. I felt sticky and filthy with sweat. My clothes got drenched. I wilted like a neglected daisy.

(And there were insects that lit up at sunset and other insects that made weird mating noises ALL THE TIME. Freaky. /derail)

The upshot is, I prefer to stay in an area where moisture precipitates out of the air when it is appropriate instead of hanging around and making people miserable.
 
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Travis said:
I live in California. And each summer we will get a few bad heatwaves. While I'm sweltering under 115F (46C) conditions I'll suddenly have someone on the internet tell me that "at least it is a dry heat!" Which sort of makes me want to punch the wall. Which I won't do....of course because of the heat that I apparently shouldn't even notice. :rolleyes:

So....dry heat vs humid heat.

DRY HEAT|HUMID HEAT
Easy to dehydrate|Easy to get heat stroke

Which is truly worse?
Click to expand...

I've lived and worked in the desert, and I've lived and worked in a jungle.

I'll take the desert.
 
Travis said:
DRY HEAT|HUMID HEAT
Easy to dehydrate|Easy to get heat stroke

Which is truly worse?
Click to expand...

More humidity at any given temperature is definitely worse. And high humidity doesn't prevent dehydration. You sweat just as much, it just doesn't cool you off as well.

The problem with the comparison, though, is that relative and even absolute humidity are often lower when the temperature gets extremely high, so quite frequently we aren't interested in comparisons of the same temperature at different humidity levels, since the factors that lead to high humidity (ie, lots of water evaporation) also act to slow temperature increase. And it's obvious that even compared to 90% relative humidity and 100 F (which is admittedly miserable), there is some temperature at which even 0% humidity is still worse. So there's some tradeoff, and the heat index is intended to capture the basics of that tradeoff. If one were to draw out a chart of temperature versus humidity, there should be sloped lines of equi-misery: if one increases temperature but decreases humidity by the proper amounts (or vice versa), one should be able to maintain a constant level of discomfort. But I doubt that chart is truly universal, it probably varies between individuals based on their particular physiology. The heat index is just an attempted approximation of an average.
 
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