From a Washington Post story by Andrea Salcedo headlined “Where the most U.S. residents bake because of concrete and lack of trees”:

All U.S. cities experience some level of “heat island effect,” in which heat reflects off hard surfaces, intensifying the impact of the hottest days. But as climate change intensifies, nine U.S. cities are special islands unto themselves, according to an analysis released that coincides with a heat wave enveloping much of the nation.