Just ride. It's really not very hot in Davis, it's just the change from winter that creates the illusion of heat. The first day in the 90s always seems hot in the Spring and the first day below 90 always seems cold in the Fall. By the time it warms up (over 110), you'll be ready for it IF you ride often in the moderately warm temps. you have now. Heck, it's not even supposed to go over 100 until next week. If you are living inside an air-conditioned building, do what you can to turn the thermostat up (turn it off at home). Even comfortable temps in the 90s can feel hot if you are coming out of a refrigerator.
Okay, one more suggestion. Leave your synthetics home and ride in a cotton shirt. It holds your sweat against you as it evaporates and doesn't stop the wind, both of which help you cool. If you are really having a bit of trouble, just pour a bit of water on your shirt and it'll be March in no time.
Last edited by TheHen; 06-14-11 at 08:12 PM.