Quote Originally Posted by KSH
I live in Texas, and during the summer I ride in 90-100F weather.

It really is something you have to get use to. The more you do it, the better it gets. Last week, I nearly died trying to ride on a really hot day... but over the weekend I was fine. I just had to get adjusted.

It is really important that you DRINK LOTS OF WATER/SPORTS DRINK! One bottle will NOT cut it in that kind of heat. If I do a challenging 30 mile ride, I can drink through 1.5 liters in my Camelbac and 24oz in my water bottle.
If you have a Camelbac and put ice/water in there... it will stay cool for a good 2-3 hours.

Finally, LISTEN TO YOUR BODY. Learn what heat stroke/exhaustion is. And when you feel it happening, stop riding and take care of yourself.

Best of luck! Trust me, it gets better the more you do it!
I live in Seattle, we rarely have heat. when we have it, I am a mess. So even without personal knowledge of dealing with heat, i implore you to
please follow this gal's directions because heat can kill. I have been through several CPR and first aide classes, this stuff is no joke.
Mimi