The Sun sets.... so why does it feel hotter overnight?

[hmmm27]

TL;DR Summary

When I was a kid, nobody had air-conditioning. At the end of a hot, muggy day we'd find it impossible to sleep, drenched in sweat...

I've always wondered why.
Would the reason be that the air cools but the amount of moisture stays the same... which makes sweating less effective... which means no cooling effect even though the air is technically cooler.

 

[Drakkith]

It might have something to do with your body temperature increasing over the course of the day. I always have to bump down my AC from 78 to 74 (or less) to stay comfortable in the evenings before I go to bed. But that's pure speculation on my end.

In any case, I'd be willing to bet it's more perception than an actual difference in the air.

Would the reason be that the air cools but the amount of moisture stays the same...

According to wiki:
"Although humidity is an important factor for thermal comfort, humans are more sensitive to variations in temperature than they are to changes in relative humidity."

 

[Tom.G]

Just to point out the obvious, a substantial portion of your body is well insulated when in contact with the mattress.

Also convection cooling is inhibited by being so close to the mattress. A low speed fan in the bedroon can help immensly.

Cheers,
Tom