one of my boys lives in AZ. It's very hot and dry and to my surprise, there are quite a few beekeepers. Water is a big thing. Like most critters, if bees have basics like food and water, they can regulate their environment pretty well. The hives I saw were not even shaded, although I don't know what is done in the hottest part of summer.
They get a big bloom with the monsoon rains, but that does not last long so everything that is gathered has to be done in a short period of time unless there are irrigated crops around.