Daniel Swain in Tuscon.com: August just replaced July as Tucson’s hottest month ever recorded

August was Tucson’s hottest month ever recorded, with sizzling temperatures breaking the previous record — set in July. That means a greater fraction of solar energy goes directly into heating the air, rather than evaporating water from the soil — making temperatures quite a bit hotter than they would be otherwise, said Daniel Swain, a UCLA climate scientist.