A relentless heat wave now stretches across most of the country. Residents live under oppressive alerts as thermometers spike past triple digits in countless states. D.C. could tie daily benchmarks this week. New York City turned cooling centers like museums and train hubs into relief zones for Fourth of July visitors. The city now faces dangerous highs too . Forecasters extended warnings from the Midwest all the way to the East Coast.
Doctors caution heat exhaustion and dehydration may turn deadly fast . Cities unlocked extra rec centers and malls for community comfort. Forecasters see little change through the coming days .