The nation's fifth-largest city sprawls across 520 square miles of Sonoran Desert, where the Salt River once flowed before dams controlled its course. The metropolitan area's 4.9 million residents endure extreme heat, with summer temperatures regularly exceeding 110°F for weeks. Winter brings perfect weather, with daytime temperatures in the 60s and 70s attracting seasonal residents from colder climates. Mountains ring the Valley of the Sun: the McDowell Range to the northeast, South Mountain to the south. Minimal annual rainfall of 8 inches means the Colorado River sustains all development. Fall temperatures remain hot into November.
