I voted for no change. While no one enjoys when its 120, if you didn't have those extreme temperatures you'd have vastly different flora and fauna, which I wouldnt want. I love the sonoran desert and think its beautiful, changing the temperatures would radically change how it looks, so that would be right out.
Now if we're in some sort of fantasy land vaccuum where weather somehow doesn't make any difference in that area, then Id just make it a high of 88, partly cloudy every day.
Don, if you're cold, perhaps try longer shorts, just an idea