I've only experience 100+ F. for a couple of days in the South of France and it was unbearable.
I seem to have the ability to manage well enough in the heat - and it is not only the heat, wet bulb is high as well. I walk every day about 5 miles when I am not cycling, and when I finish my clothing is saturated. I think standing around in the full sun is hard for most people though, moving to get the air flowing is best. Anyway, unbearable or not, surprisingly one can get used to the conditions. In any case, the temperature is rising everywhere, so we'd better get used to living in it.