I'm with MomOnBike; anything over 70 degrees is too hot! The only thing I hate worse than the heat is wind. I base my choice of bike path on which way the wind is coming from. But, back to temperature. I had some problems riding in the 50 degree range until I got better clothing. But appropriate clothing didn't help me much with the heat. In Ohio it is so humid in the summer, that 85 degrees with 80% humidity just kills me. I haven't found much of a solution for that problem. I'd much rather ride when it's cool.