In this Friday, June 3, 2016 photo at Mount Lemmon, just north of Tucson, Ariz., students sit on a large rock overlooking the landscape. Many in Tucson escape to Mount Lemmon as temperatures rise to triple-digits, heading warnings of excessive heat. Mount Lemmon is the highest point in the Santa Catalina Mountains and offers temperatures that are on average 20 degrees cooler than the city. (Photo by Astrid Galvan/AP Photo)
