The threat of temperatures climbing above 90 degrees and a grueling climb couldn't stop the die-hard cyclists and spectators from making the trek up Mt. Diablo. Of course the key was to stay hydrated.
The longest line at the junction ranger station wasn't for the restroom, it was for the drinking fountain.
"Yeah, it's really hot out here. We came last year and two years ago we camped up here and it's really fun," Jimmy Hutson of Lafayette said.
In the end, seeing some of the best riders in the world scale a mountain was well worth weathering the heat.
Medical staff were close by.
"We travel with two ambulances. We have five race doctors in the race actually traveling in convertibles so they can administer first aid to the riders as they're going down the road. It's pretty interesting to see," said Course Director Eric Smith.
Cycling in hot weather isn't that unusual; last year riders endured 114 degree temperatures during a stage in Palm Springs. Keeping the riders hydrated and cool is tough. Skratch labs brought 200 plus sports drinks and 700 rice cakes to hand out to riders on the course. Skratch's founder and exercise physiologist Allen Lim says riders can sweat two to three liters an hour and burn up to 4,000 calories during the entire stage.
"What I expect for these riders today is a lot of pain and a lot of suffering. There's really no way around that. That's kind of the beauty of cycling and that's what makes these athletes so amazing," said Lim.