I don't know about Vegas, but I didn't have AC till I was 19. As I said above, temps were usually 90's with a few days of triple digits. We farmed so we were up and out the door by 5:00, and tried to have all the under the sun work done by 11:00. From 11:00 till 18:00 we tried to work in the shade, after that we finished anything that was directly under the sun.
Sleeping in that weather was an absolute bitch, you just lay in bed sweating till you passed out. Britain has some of the most mild climate on earth, so I'm gonna stick with weather wusses