I've been to Phoenix in the summer twice for work. You can get great hotel rates in the off season, so we've had meetings there. It is indeed 110 degrees every day, and you just go from air conditioned space to air conditioned space. And despite the supposed dry heat, what they don't tell you about is the "monsoon" phenomena, which is like humid dust storms that make things really miserable.
Dallas is no Pheonix but I’ve been there in August and it hit 110 and near there days on end. Weeks of above 100. Indeed it’s the opposite of winter with the AC. Parking lots are murder.
Yeah, June and July in much of Arizona is hot and humid because of the monsoons. July in Phonix can be120 and clammy.