Sweltering heat wave grips central and southern US for a second straight day

A heat wave affecting 40 million people in central and southern US regions persisted for a second day, with heat indexes exceeding 105°F and some areas reaching 120°F. The National Weather Service attributed the extreme temperatures to a heat dome, leading to canceled events like a horse race in Minnesota and warnings about health risks for vulnerable groups. Moist air also increased severe weather risks around the Great Lakes.