Runners wearing Independence Day-themed items jog at dawn past an overlook in Arlington, Va., as Washington prepares for sweltering temperatures, Friday, July 3, 2026. (AP Photo/J. Scott Applewhite)

A member of the Texas State Troopers pours cold water over his head during an extreme head advisory near the Lincoln Memorial, while providing extra security ahead of the America 250 July 4th celebration, Thursday, July 2, 2026, in Washington. (AP Photo/Nathan Howard)

Visitors react to the heat while attending the Great American State Fair on the National Mall, Wednesday, July 1, 2026, in Washington. (AP Photo/Nathan Howard)

Zookeeper Brooke Cannon feeds Nigerian dwarf goats frozen pellets at the Franklin Park Zoo in Boston, Thursday, July 2, 2026, to help them cope with the hot conditions. (AP Photo/Michael Casey)

An African penguin swims in their enclosure at the Franklin Park Zoo in Boston to cope with the hot weather conditions, Thursday, July 2, 2026. (AP/Michael Casey)

Zookeeper Brooke Cannon provides a Dexter steer at the Franklin Park Zoo in Boston, Thursday, July 2, 2026, with a block of ice containing apple slices, bananas and pears to help it keep cool amid the heat wave. (AP Photo/Michael Casey)

A pygmy hippopotamus wallows in the water in their enclosure at the Franklin Park Zoo in Boston to cope with the hot weather conditions, Thursday, July 2, 2026. (AP/Michael Casey)

A man plays Frisbee with friends in the Sheep Meadow of New York's Central Park, Thursday, July 2, 2026. (AP Photo/Richard Drew)