They say that, but I was just there last month hiking inside the grand canyon where the thermometer was 116 inside the canyon floor. No such thing as dry heat, its hot as **** out there. I drank gallons of water and my body after 16 miles of hiking shut down. Took 3-4 hours after I finished to process water again. It was beginning stages of heat stroke. We passed a girl with 5 EMTS around her throwing up. She had to be carried out.