Don't wear shorts, and mesh pants in 100+ degree weather..the hot air on your legs is scorching at freeway speeds~!! hahaha
You might want to czech out some of the Tiez Mesh riding suits - one of this site's sponsors - nice stuff too.
Welcome to Teiz Motorsports -
No matter what pant you select, even the mesh ones will be hot when you're sitting there, stopped in traffic, wearing a sweaty helmet, etc....It's part of the fun :headbang:. Summers in Michigan can be unbearably hot and humid, but I've found that my Speed & Strength Hell and Back pants work remarkably well in jungle-like conditions. The pants have a 4" wide panel that's about 1.5 feet long on each front thigh, that zips off to reveal mesh (the grey diagonal panels on each leg). The pant leg is cut for wearing over the boots, so between the generous hem opening, and the thigh vents - at anything above a crawl, these pants move air. And you avoid that irritating wind-on-skin feeling at freeway speeds.
On hot days, I wear only bicycle shorts underneath, or some of my favorite street shorts. They're great pants and I like that I can take em off when I arrive and lounge about in my normal street wear - that's fun. With colder weather, the panels installed, and even the liner installed, they are a true all season pant. Well constructed, velcro hip clinchers that actually have a useful range of adjustment, removable hip and knee pads are all well thought out. Not cheap, but not the most spendy. Worth a look.