"Our hottest day was 117 and it hit in June," There must be some frost impeding the operation of your thermometer. - We frequently have such temperatures in the inland bay area, and we're 500 miles north of you and a couple of thousand feet lower in elevation. - Back in the 50's it would hit 120 F. in Walnut Creek at least 4 or 5 times per year; now it never makes it that high.
These cold summers suck, don't they? I am trying to remember the last time I saw triple digits on successive days in the South Bay or East Bay. They start getting all excited these days when it hits 90 at Moffett Field. Then I love it when all the greenhorn / carpetbagger transplants start to bitch when it gets above 80 (or above 70 around the Golden Gate!).... "it's SOOOOOO hot... when will it get back to normal?" What a bunch of whiners!
Tucson is in a wierd dip or something. Phoenix, 100 miles straight north from here, is generally hotter than us. We've always had cooler temperatures than places you think should be cooler than us. Remember distance from the equator isn't the only determiner, altitude has an effect, and so does the terrain. We've learned that highly reflective ground surfaces (like concrete, or some types of sand) raise temperatures. There's probably other stuff too that I'm just not smart enoughto know about.
Of course we still spike up over 100 regularly, and over 110 a couple times a year. Once you get in that range it's just HOT and the actual number isn't that important.
So according to our impromptu and highly unscientific study the desert areas are getting cooler. Maybe that's the cause of global warming, maybe that desert heat is finally dispersing over the rest of the planet. That's as good an explanation as what the envirowhackos are proposing.