It's not true that Phoenix has no seasons. Not even the joke that they are "hot, hotter, hottest, and hell." They just change with a sublime nuance. Or this was once the case. Leaving the delightful 70s in Seattle, I am here for 110, headed to 111. This is five to six degrees hotter for this time of year than normal. Summer temperatures have risen about 10 degrees in my lifetime, especially the overnight lows. And summer is lasting longer.
This is mostly the result of "local warming," where the farms, groves, and desert have been replaced by sprawl and gravel, along with the destruction of thousands of shade trees and the grass and landscaping that made the city more beautiful and livable. I suspect that few people know this or even notice it. For one thing, Phoenix suffers from a high rate of population churn. And many of today's residents are here for the heat, "the hotter the better." Advanced automobile air conditioning and air-conditioned houses cloak the danger of this human-made environment. So when all the asphalt, concrete, and fruit of the Arizona Rock Products Association release the accumulated heat after sunset, so what?
Consequences abound. Several large wildfires have raged. I also notice on the Phoenix Fire Department regional dispatch site a significant uptick in brush fires, requiring significant commitment of apparatus to knock down. One reason is the expanding exurban development into the desert. Fools go hiking and mountain climbing in this weather. That was once rare. Summer was the time to spend inside, especially during the day (when the nights cooled down). When I was a paramedic in the 1970s, a summer mountain rescue was extremely rare. No more. Now, multiple rescues happen every day, putting first responders at risk and the "victims" often near death.