It might be better to look at it as a "strategically timed" car wash. Its so dusty in the summer your windshield can be hard to see out of. We have little humidity in July. Just horrid oven like heat. We open the door and windows to get the air out too. Probably the lack of humidity in June / July allows this to work in a way it would not in non-desert places.

Also after a week or two over 115, 110 feels absolutely "cool" to us here in Phoenix. We really do say "Hey, today the high is only 110! Fall is coming!".