My preferred riding time in the summer is 9:00am - 10:30am. Too early, and the dew point and temperature are too close for comfort, meaning the air is saturated with moisture. On any given day though, the dew point doesn't generally drop drastically later in the day, meaning there is just as much moisture in the air but at much higher temps. Late morning is the perfect compromise IMO because the temps are high enough to allow some evaporative cooling, but not so high that they raise your body temperature even when you're standing still. I rode Friday night from 6:30 to 8:30, and that first hour was brutal. Temp was 96 but "feel like" was 102. Of course it also depends a lot on how much you exert yourself, and Double Down probably wasn't the right place to start my ride that night.