Some additional suggestions for toasty weather riding.
Choose your riding gear carefully, but go ATGATT. Good mesh riding gear will allow some airflow, yet keep you on the positive side of the evaporative cooling vs. evaporative dessication divide. You may feel slightly cooler without the riding gear, but you will lose water much quicker. Dehydration and heat injury are both risks, and its possible to incur one without the other. Uncommon, yes, but possible. Minimize black gear, get the lightest color gear you can live with. Yes, it will show the dirt quick, but it won't soak up the heat nearly as much. Ditto for your helmet. A white or silver helmet will be cooler than a black helmet.
When its really toasty and you stop someplace where you're going to go inside, get off the bike, take your keys and GO INSIDE. Don't waste time taking your gear off outside, just get inside. Once you lose the cooling breeze, you'll start to heat up very fast in the riding gear, especially since you're probably standing in the midst of an asphalt or concrete baking stone, er, parking lot. Of course, certain places (such as banks) may require rethinking this option, i.e. taking your helmet off on the way inside.
Chapstick.
Your rightside fairing pocket makes a good drink holder. Styrofoam cups will do a pretty good job of keeping your drink cold, even when its ahunnertandteen degrees hot outside with the added bonus of the engine heat coming from below. Take advantage of the fairing pocket!
Salt. If you're out riding extensively in the heat, skip the low salt diet unless you've got a bonafide medical condition. This doesn't mean load up on salt, just don't work to reduce salt intake.
I generally ride in T-shirt or lightweight long sleeve travel shirt and lightweight nylon travel pants (the convertible type) under my mesh gear. REI's Sahara shirt and pants are good examples. Just enough to keep the hot wind off the skin, but otherwise light and comfy, plus when I get where I'm going, I don't have to mess with sunscreen. (As an added bonus, I can carry three complete changes of clothing in one saddlebag!)
Vented boots, if you can find them.
Sports drinks are not the enemy, just water them down. Drinking ONLY water when sweating a lot runs the risk of mineral depletion. Diluted sports drinks will replenish the minerals. Full strength ain't necessary since we aren't workin' nearly as hard as athletes, plus diluted is easier on the stomach.
Caffeine is problematic. It is a diuretic. Coffee and "energy drinks" are the worst culprits.
Slurpees - wonderful, but beware the brain freeze!!!