Tuesday in Phoenix, Arizona, the temperature kept some planes grounded.
Phoenix was projected to reach of 120 degrees Fahrenheit, a near-record for the desert city, and hot enough that small planes cannot generate enough lift to fly. Phoenix and other cities have experienced similar conditions before, but only rarely—for now. The grounded passengers got to sit inside an air-conditioned terminal, at least. But in other parts of the world where temperatures are set to soar regularly above 1