I went riding yesterday: In Washington, DC, the temps were in the 90s, heat index above 100, and on the thermostat on my bike, the temp never dropped below 102. I was born and raised in this area, so I'm quite familiar with DC area heat and humidity. Yesterday it was so hot, the politicians made their interns yell at each other. (badabump-tash!)
I rode to north Frederick via side roads, which meant shady trees and slight breezes. I had on a long-sleeve T-shirt, vented Olympia jacket (black) and Ironworks rider's cargo pants (also black). Normally I'd ride with vented Olympia overpants over regular pants or shorts, but I wanted to see how the Ironworks felt. On the way up, as long as I had roads with as little as 20% shade on the road, or was moving at a good pace, I felt perfectly comfortable in all that black.
The way back was a bit different: My stock seat started to get hot, especially the 2 times I stopped and got off for a bit. Combined with the Ironworks pants, my butt started to feel like it was an ironworks. Probably from squirming around, I must have pinched off a nerve, because my brake foot fell asleep, and I caught he!! trying to wake it back up while on the road!
Anyway, made it home after going through about an 80-90-mile trip, got out of those pants, changed my T, and I was good. I think I still prefer the overpants, especially on really hot days (worse comes to worse, I can always find a bathroom and wear the overpants without trousers underneath). But I guess the Ironworks work in a pinch, in temps below 90 at least.
You can't take the ride from me.