Well...that was interesting. Haven't ridden in about six months. It was a little over 100 degrees today, and I decided it would be a good idea to take an 8.5 mile ride in the midday sun on my two year old $100 walmart POC 40lb mountain bike with 2.5" knobbies. I'm not sure I've ever sweated that much. Averaged 13 mph on a bike path over rolling hills. Not too bad but I'm way out of shape. Gotta start riding more.
My advice to all of you- When it's over 100 degress with 50% humidity, fun as biking might be, stay inside, especially when you're out of shape.