I lived in Tucson for 3 years and it goes without saying you don’t ride as hard at high temps as you do in normal weather. But riding in heat is totally doable. Your attitude has to be to ride mellow… for fun. Not pushing the limits, lots of breaks and pay attention to your body (if you notice you aren’t sweating you have screwed something up and you need to immediately complete your activity.) It is nearly impossible to recover on your own (during a physical activity) if you mistakenly push yourself past safe. You’ll have to seek rest, cooling, hydration and seriously consider medical attention. Have a safe "plan b" in your back pocket. Wife who can get to your location with a car or buddy’s riding with you or whatever. Just have a backup plan.
I had to work out in the desert on foot quite a bit too. So the same goes for hiking. We were normally carrying a lot of gear and participating in rescues of distressed individuals. You build up to it. Your body will definitely acclimate as the summer goes on. You start working in distance/time/exertion gradually.
That is my 2 cents.