A youth football coach sweats as he loads water and Gatorade into a cooler to put in his car ahead of a summer football camp, during a heat wave on the West Side of Chicago, Illinois, on July 2, 2026. Blistering temperatures and humidity gripped swaths of the United States on July 1, with the worst yet to come for the densely populated East Coast as the nation co-hosts the World Cup and prepares to celebrate its 250th birthday. "Heat dome" conditions -- in which high-pressure systems trap warm air like the lid on a pot -- persisted over the Midwest and South and were moving east, with some 46 million people under heat alerts. (Photo by OCTAVIO JONES / AFP via Getty Images)