2 tips for hot weather big walls
This tip come from big wall expert Andy Kirkpatrick. Check out his excellent book on big wall climbing, “Higher Education.”
Yosemite valley or Zion in the summer can be a reflector oven on a big wall. If you find yourself in the heat, here's two easy ways to stay a bit cooler.
small folding umbrella
water mist/spray bottle
Between some instant shade and evaporative cooling, you can stay a lot more comfortable at that multi-hour belay.
And, that will give you some time to think about why most people like to climb in Zion and Yosemite Valley in the spring and autumn. :-)
If you're in Yosemite in the summer and want to climb, consider heading to the higher elevation Tuolumne Meadows area.