seriously? Does it bother you that much? I'm in AZ and I go to the range weekly for 3-4 hours at a time, every time in the last 2 months it has been between 100-115 F. Wear a shirt and shorts, and who cares if you sweat? Unless you have some kind of health condition, I don't see why it should be a problem.
I guess my range DOES have a metal piece over were your shooting, so im not in direct sunlight 90% of the time. If you are, then that would get a lot tougher, but wear a hat and sunscreen and thats it.
It will also be good practice battling with mirage..... quite interesting trying to achieve tight groups, when the .5MOA dot your aiming for at 200 yards is just dancing around because its 115 outside....