Guess I'm pretty dumb... I rode across I80 from Cali to Ohio in July...wearing a heavy leather jacket, leather pants, gloves and a ff helmet and boots.
Actually was quite comfortable all zipped up until the tempos got over 100f. then it got a bit warm.
bad thing was my jacket faded on the wrinkles...

(
I also use sunblock, except on my forehead, don't like it dripping in my eyes. You can get a sunburn thru a clear visor....<G>
mary