We have been in AZ 21 years now. We moved from Scottsdale to the SE valley, about 45 minutes SE of Phoenix, about five years ago. The Phoenix metro area is in the low Sonoran desert which is a bowl that holds heat for about three months. The high summer temps here run late July through September/early October. The high heat breaks in October, sometimes overnight, but we’ve had warm Halloweens.
What people need to understand about temperatures here is that we generally have a 30-degree daily spread, and temps in the 90’s are quite comfortable and feel nothing like those same temps in the east, Midwest, or anyplace with humidity. Temps in the 70’s can feel downright cold. It’s hard for people to fathom being outdoors comfortably in the 90’s-low 100’s, but you have to experience it to understand it. So, don’t feel sorry for us until you see the temperature go above 105, which seems to be the tipping point between quite warm and very hot. And, no, I have not acclimated; I hate heat.
Where this scenario changes is when we hit monsoon season (where we are now), when the dew point goes above 60, and the storms bring humidity. Then, we lose the 30-degree spread, humidity rises, and all bets are off. For me, the valley is miserable about 10-12 weeks out of the year. The rest of the year is paradise.
Right now, the daily lows have been in the low-to-mid 80’s, with the lowest temps (obviously) just prior to full sunrise. We walk between 5-6AM. There is no time during the day or early evening when I find it bearable to be outside during monsoon season.
Looking at the weather forecast (high/low) right now for the upcoming week:
Today 102/80
Sunday 89/76 (due to thunderstorms)
Monday 93/75
Tuesday 96/75
Wednesday 98/78
Thursday. 102/78
Friday 105/80
Saturday 107/82
These are unseasonably low temps, but the thunderstorms will bring sauna-like humidity. Think of the effect of dropping water on a frying pan; that’s AZ monsoon season, so those lower temps look good but will feel miserable. Those same temps with no humidity earlier in the summer would have us all back on our patios partying. Well, not during these times, but you get the drift.
So, the old cliche, “It’s not the temp, it’s the humidity” holds as true in AZ as it does anywhere else. We’re just blessed not to have that humidity for very long.
One word about monsoon storms: We don’t get as many as we used to, but they are a spectacle to behold. I’d never seen lightening skip sideways across mountaintops or bone-dry land become a rushing river in a matter of minutes before moving here. Our first few summers, we’d either turns off all our lights to watch the light show outside, or we’d drive to an area where we could see the lightening skipping across the ring of mountains around us. We thought we were in the midst of a National Geographic photo shoot. I still find them breathtaking.
ETA: Arizonans value monsoon season as a way of keeping people from moving here. 
