120F is not lethal when the humidity is low, you're in the shade, and you have water. I lived in Tempe for six years, and it was regularly 115F+ in the summer,

120F is not lethal when the humidity is low, you're in the shade, and you have water. I lived in Tempe for six years, and it was regularly 115F+ in the summer, hit 118F a handful of times when I was there, and that's not counting the extra heat if you're standing in a parking lot. I used to bicycle four miles to work when it was 115F, and walked a couple times. If you look at the Wikipedia climate tables for Slab City and Tempe, they're basically identical. You're correct that it's lethal if you're unprepared, but so are plenty of other places and temperatures at both ends of the spectrum. I wouldn't want to sleep without AC in that kind of heat. But humans have survived temperatures like that for all of history.