I went to the Grand Canyon last Sunday and it was amazing. We ran the gamut of weather: extreme heat, glaring sun in a clear sky, huge storm, dropping temps, etc. It was very cool and really drove home the power and unpredictability of nature. In the rainstorm, it dropped 25 degrees in a matter of minutes and the storm dropped hail. Hail! At the Grand Canyon in August! It blew my mind.