Heat is very relative. I spend all day going from my air conditioned house to my air conditioned car to an air conditioned work place yet I think nothing of going backpacking when it's 90 out. Same goes for biking. I haven't found a temp that is too yet because the only time I feel hot is when I stop. For you (Mi) and I(OH) it's probably more about humidity than heat. LOL! Screw it man! Ride whatever ya want as long as you're riding.