Fig. 1. An illustration of diurnal temperature variation at 30.29N -97.74W on June 30, 2005.
It's 91 degrees at 10:30 p.m. It seems even warmer right now than this afternoon, when it was 100, probably because the heat is unexpected. You look outside, it's dark, you figure there's probably some cool night air out there, maybe a breeze. But the darkness is a total lie; you walk outside and it's so hot and still that it's difficult to breathe for a second.
Luckily, my office, car, and house are air conditioned, and if scuttling between those three doesn't work, I have a fresh stash of popsicles in the freezers at work and at home.