It hit 108 here in Chino Hills today. I left to ride at sunset and it was still in the upper 90's and pretty uncomfortable (for me at least). I can't imagine riding in direct sunlight in that sort of heat. I'm taking tomorrow off and waiting for the cooler temps Sunday. I actually flew in from Phoenix today where it was only in the mid 90's.
I rode most of the way up to the shack Sunday Evening. Gates are still closed so no traffic but the ride was nice. Stupid me forgot to check the batteries in my light so I did not want to get caught descending GMR with no headlight.