A brutal heat wave now blankets most of the country. Millions live under heat advisories as thermometers spike past triple digits in numerous states. D.C. could set new records this week. New York City turned cooling centers like museums and train hubs into sanctuaries for Fourth of July visitors. Boston now warns of dangerous highs too . Officials extended warnings from the Midwest down to the East Coast.
Doctors caution heat exhaustion and dehydration might turn deadly within hours. Cities set up extra rec centers and malls for community comfort. Models predict little change for days ahead.