If you aren't out on the road by 8:30 around here, you're better off staying home until just before sunset. By 10:00 it is usually in the upper 80's/low 90's which takes all the fun out of it for me. I am trying to get out by 8:00 during the summer. In the winter I wait until mid morning for it to warm up a little. There is a noticable difference in the amount of wind first thing in the morning and my local trail is mostly shady as the sun is still low. By 10-11 it is high enough that most of the trail is in blazing sun - no thanks! (I admit it, I'm a wimp)