Grand Canyon National Park Summer Thunderstorm Crossing Canyon

July, 21, 2013. The view is from Shoshone Point on the South Rim. NPS photo by Michael Quinn. Summer thunderstorms (July – September) provide beauty, excitement, and much needed water to Grand Canyon, but they also bring risk. Dangerous, potentially deadly, lightning accompanies thunderstorms. Lightning has killed and injured visitors to the park. While absolute safety from lightning cannot be assured, knowledge and good judgment can help you reduce risk. Learn lightning dangers, practice basic safety precautions, and instruct your children to be aware.