[dentheman]

It's supposed to get up to 99 here today. Might as well be 100 as far as I am concerned. I now ride in the evenings, starting around sunset, when it has cooled a little.
One thing I have noticed is at dusk it remains hot in the city, but when I hit the country roads going through pastures or crops it is noticeably cooler, almost like a slap in the face it is so noticeable. Unfortunately, bugs also like those cooler areas so I come home with plenty of bug remains.
I have found that my modular helmet is no hotter than my 3/4 with faceshield. The chin vent directs a good stream of air over my face and through the helmet. That air feels cooler than the outside, and if I am moving slowly or stopped, opening the faceshield a bit works well.
I have a mesh fabric jacket that has shoulder and elbow armor as well as back and kidney area padding. It is a Tourmaster that has the removeable non-mesh outer jacket and the removeable inner quilt lining, I have not used either of those. I think the mesh keeps me a bit cooler in the sun than a T-shirt and bare arms. After the sun goes down the mesh doesn't make much difference over bare skin, but it does provide the added armor/padding protection.
Finally, my bike doesn't like hot weather either. It sometimes doesn't want to shift into first gear when it has been ridden at highway speed during a hot day. Once the oil gets very hot I guess. On cooler days or lower speeds I never have that problem.

Also, I am looking into getting one of those cooling vests that is 'charged' by soaking in water, to wear under the mesh.