What's funny is that I used to live in Phoenix for a year. I would happily take the higher dry heat over the almost as high wet heat. When I lived there it was like walking into an oven and you could feel your sweat pours opening. But the sweating evaporated quickly and provided cooling as long as you stayed hydrated. Shade works and you can see how the natives protected themselves from the sun and had passive cooling that worked. In the wet heat it is more like Satan is pissing on you and you have no hope. Your body is dumping sweat and it does nothing because the humidity is too high to evaporate. Shade? Worthless beyond the immediate sun protection. A few degrees at most. Without AC you will only cool with high winds or a fan.

Fun fact I never knew until living there: when it hits 112 (and it does) the airport has to partially shut down and divert all non-high-temp aircraft. The tarmac is so hot it will pop normal tires at a high rate. So unless you have the expensive higher temp rated tires for planes based out of high temp areas, then you can't land there when it is too hot.