There was a divisional race here a few years ago that they had to stop between 1-6pm every day because it was 110+. They even took the water truck and sprayed down the track and then re-prepped for the night half of racing each day. I was down at Cocopah in Yuma when it was 120, tried to run some hot laps and could not keep any moisture in the track and pushed everything back a few hours.
My favorite "heat story" was when I took your dad to Denver and the first day we got there I was helping push his wheelchair up the hill on the south side behind the entrance to the staging lanes. Well the last time I was there I was ten years younger and probably 40 lbs lighter so I did not think it would be a challenge. I was wrong, my fatass what out of breath and worn out. Also funny story from that weekend, I forgot what day it was but we were heading back to my truck and I remember there was a hill section that led to the parking lot and I thought he was goofing off and "drifting" his wheelchair well turns out he was actually sliding down and could not control it, he ended up ramming into my tire. After I made sure he was ok, he said, "I did not know if you were able to catch me so I aimed for the tire". I joked with him next time aim for the body because we need the tire to get home, I'm ok with a dented body...
