Enjoying 60degree days w/ 30+degree nights here in Md. I went out to do 15-20miles yesterday, and w/ the temp gradually droppping toward it getting dark, my muscles were cold . I spinner the better part of the ride,however I pushed it on one busy stretch to try to get away from rush hour traffic and caught a bad cramp in my calf. Take it from me, go easy in the cooler temps, look to just collect miles and turn the crank.