I was just thinking about the heat and all. The human body can’t go much over 100 degrees F and survive. The body creates heat and has to get rid of it. It does this through conduction and radiation, and it also sheds heat through evaporative cooling. If the humidity is at 100%, does evaporative cooling become impossible? Wouldn’t that mean that there would be no way to keep the body below the ambient temperature, and thus death would be certain above 100 or 105 degrees at 100% humidity?
You would not be asking this question if you had lived in Houston.
Based on what I’m finding with a quick Google search, such a condition doesn’t seem to be possible (or, at least, it’s never been recorded as having naturally occurring).
A relative humidity of 100% means that the air temperature, and the dew point (the temperature at which the air would be 100% saturated with water, given the current amount of water vapor in the air) are the same. So, for an air temperature of 105 degrees, the dew point would have to also be 105 degrees.
What I’m finding in a quick search is that the highest recorded dew points are in the very low 90s (and those seem to mostly occur in and around the Persian Gulf). Still incredibly uncomfortable, and probably very unhealthy (especially for those with health issues in the first place), but not exactly the situation you’ve described.
This got me interested and I ended up in a wikipedia loop, reading several pages that may or may not have been related to the question. I stumbled across these interesting tidbits from the heat index wikipedia page:
So, apparently, you can get 100°F/100% humidity in a sauna and people do survive in there, but I can’t tell if the last sentence is talking about life not persisting for long means at 100/100 or if it’s talking about temperatures above that.
Or Dallas.
Orlando gets this bad a few days a year, and we all survive ok, minus some elderly. Still, I feel it would all go to hell in a handbasket after a week.
At 100% humidity that just means you’re walking around in a fog all the time.
I’d like to know how high the heat index has gotten here in Phoenix. When the monsoons start (around now, actually), we sometimes get those extreme triple-digit temperatures mixed with quite a bit of humidity.
I’ve read that we typically have the highest heat index in the country during the summer (so pbthbthbth to those “it’s a dry heat” people) simply because we’re often starting with temperatures of 110+ before even factoring in our (admittedly low, usually) humidity.
I just had to register and reply to this - I’m not sure who wrote that in Wikipedia, but it is painfully wrong at least as far as Finnish sauna is concerned. Typical sauna temperatures here in Finland range from 70 C to 110 C (and can go over 120 C), but the humidity is low. Maybe it is refering to Turkish sauna or some other sort of steam bath?
No idea what the heat index is in 120 C sauna, but that sort of temperatures are tolerable for 10-15 minutes.
I agree. I thought it sounded off too. I’ve never been in a sauna in Finland but I’ve been in one ~50 miles away in Estonia. It was dry and about 112C. Not Fahrenheit. It was so hot that I was told to keep my hand over the mouth of my beer can or else it would burn me when I tried to take a drink. We stayed in maybe 10 to 15 minutes.
Getting back to the OP, I’m certain that you understand the issues correctly and that having the temperature at 100 F with the humidity 100% would create an unsurvivable environment. This is the same thing as saying the temperature and dew point both at 100 F.
It’s a separate question whether this occurs outdoors due to weather, which I don’t know. But there’s no physical reason it can’t and I’m sure it’s happened at some points in Earth’s history. 100% RH, by the way, isn’t the same as fog. In fog and inside clouds, you typically have over 100% RH. If you want to see what 100% RH looks like, look at any clear closed container that’s partly full of water and has reached equilibrium. The air doesn’t look any different.
Dallas doesn’t get exceptional levels of humidity in the summer. It’s far enough inland.
I notice that is in the past tense.
Is someone being exposed to this in a walled cell or a natural environment? It would seem like there may be ways of getting relief if one has access to nature (water, earth (digging down)).
I checked out a sauna manufacturers webpage which also said Finnish saunas are typically dry while other saunas and steam baths are typically made around 100-120°F with 70-100% humidity. I don’t know why they stressed Finnish saunas, but if you scratch out that word and just read saunas “that use wet heat”, the numbers are still accurate.
As someone who has done dry and wet saunas, it’s incredible how much a difference the humidity makes. I believe the last steamroom I was in had a temp of 40-42C. I could barely make my way past the door. I had to breathe with my hands cupped over my face. Any movement felt like being scalded in hot water. Obviously, people had gotten used to it, as there were more experienced steambath users deeper in the chamber, having normal conversations and shaving, but to me it was excruciatingly painful. I couldn’t last more than 5 minutes. I couldn’t imagine surviving at this temperature (which was 104-108F) with 100% humidity for an extended period of time.
Posters joke about the humidity in Houston. 100% humidity with 100F temps is not in the same ballpark of what you’ll ever experience in Houston.
whats the lowest humidity anyone has actually experienced?
Well, here in Arizona we all have to walk around with PDUs (Personal Dampening Units).
Gee, I manage to do that regardless of the humidity…
You know, this whole sub-thread is cracking me up; when I read the OP, I had the exact same thought as ** Jackmanii **, and I live in Dallas, so I know how relatively NON humid it is up here usually (not at the moment; it’s been raining Houston-style for 2 weeks)
The only place I’ve been that rivals Houston is New Orleans, and even there, it’s really only obnoxiously humid in the mornings; after lunch it goes away until the following morning. But when it is humid, it’s truly terrible there.
And while I agree that you don’t get 100% humidity in natural weather, you do definitely get somewhere in the 70% range with regularity, and Houston does indeed get above 100 degrees with some frequency.
I’d say it’s likely that you could easily get 95 degrees and 70% humidity in Houston without having to really try- while not 100/100%, it’s still enough to be extraordinarily uncomfortable. Your sweat doesn’t dry; it just sort of soaks into your clothing and/or runs off, even if you’re just walking in a parking lot from your car to the store, or pumping gas.
I think you could live at 100/100%, but only for a limited amount of time, unless you were sitting on something cold, or removing the sweat and rehydrating yourself; evaporation isn’t the only heat-removal mechanism.