Ihncheol, Having lived in the desert for almost 7 years now I do know the brain will overheat before your batteries or motor.
Seriously though, I've flown up to about 104-105 out and it's not fun but doable. The hottest my batteries have gotten was ~118 and motor around 125 - 128. I have a old computer fan that I hook up to a 12v 7amp starting battery for cooling. Keep your flights short and put the fan in front of the nose right after landing.
maustin