Heat and hydration management is huge here in the desert. I've had one close call, when I got busy at work and hadn't consiously been hydrating before the ride home, when it was 116*. I added to that by running out of water a couple of miles from home. Doh! Should have stopped, but I kept riding. I had stopped sweating when I got home and was feeling really and truly messed up. A shower and fluids brought me back fairly quickly, but I learned a lesson that day. Stay ahead of the hydration curve. If you pass the tipping point, you can get in trouble fast.