Man, I didn't think it was that long since the European heatwave, and I did not remember those high death numbers.
Cooler, semi-arid nights make a big difference in places in the West that get hot during the day. One of the reasons I'm focussing on SW Idaho for retirement. Even if it's in the 90s during the day in August, it still usually drops to the high 50s at night.
I would have a hard time in some of the South, and I guess the DC area as well between the humidity and the nights not cooling as much. When I go to Hawaii, it's also humid without a lot of cooling at night (at least on the coast - the mountains can get darn right chilly), but Trade Winds make a world of difference. Stagnant, humid heat is my dreaded enemy.