Actually, lipo batteries 'like' heat. It is cold they can not tolerate. At least that's what I've read from several sources...
Are you careful not to run them down too much, and also to not charge at more than 1C?
We've had nothing but 100+ weather ever since I got my BCP, and my lipo seems just as good as always. I never fly for more than 10 mins at a time, tho... I have to let the motor cool. If I push it too long, the main motor will degrade very quickly when it is so hot.
One day about 2 weeks ago, it hit 108F here, and I was flying in it. I had to stop after about 6 mins. The main motor was so hot that it could barely hover any longer
I had to replace that motor about 1 week later.