In summer, the sun turns the desert valleys into a giant oven. When venturing into the summer heat, wear a hat, sunscreen, and a good pair of sunglasses, and drink plenty of liquids. In summer, a person can sunburn in as little as 20 minutes. The monsoon season usually begins in July and lasts about two months. During this time, the high temperatures and humidity often bring about late afternoon clouds, dust storms, lightning displays, and sometimes, rapid heavy rainstorms.
Summer storms kick up huge clouds of dust and lightning ignites brush fires.
Do not hike or climb in exposed areas when lightning threatens. Do not take shelter in shallow caves or under rock overhangs or lone trees, prime targets of lightning. Rainwater running quickly off rocky desert surfaces and into gullies becomes flash floods that can sweep away boulders, cars, campsites, and everything else. Take care not to camp or park in potential flash flood areas. A flash flood usually lasts no more than an hour or so.