Back in the good old days, before all the concrete, asphalt and steel, it used to cool off at night in the Phoenix area. The cooling effect was helped by the Salt river because at that time it was flowing.
I have been camping out in the desert in the summer and have needed a blanket at night.
Oh for sure it gets chilly sometimes. I’m on the River near Bullhead City. At night here it is usually over 100 from June through October’ish. ‘Usually’. But occasionally it cools off into the 80s. THOSE nights are awesome.