With my extremely limited knowledge of thermodynamics, it seems like high humidity would provide enough water to transfer some of the summer heat.
Is it enough to make a difference?
Prompted by my [r/unpopularopinion post](https://www.reddit.com/r/unpopularopinion/comments/ic8rd8/humid_heat_is_better_than_dry_heat/?utm_source=share&utm_medium=ios_app&utm_name=iossmf)
Thanks so much for your responses! I had no idea that cooling came from the evaporation of sweat versus the just having water on you. I was going to reply to everyone, but the response seems to be the same across the board. I really appreciated everyone taking the time to educate little ole me 🙂
In: Physics
It’s not the presence of moisture that cools, it’s the act of evaporation. Sweat has cooling power because [water soaks up heat energy when it changes from liquid to gas](https://en.wikipedia.org/wiki/Enthalpy_of_vaporization). But at a given temperature, air can only hold so much water vapor. The more humid it is, the harder it is for water to evaporate, and sweating becomes less effective.
Dry heat is dangerous not because it’s harder to cool off, but because it’s easy to become dehydrated. Since sweat evaporates instantly in a dry heat, we *feel* cool and don’t seek water.
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