Finding freedom from the heat on July 4th will be a challenge in eastern US

CONCORD, N.H. (AP) — Heat as oppressive as British colonial rule is bearing down on the eastern U.S. heading into the long Fourth of July weekend, prompting some communities to cancel, postpone or otherwise alter their Independence Day plans.

Dangerous, record-breaking heat will continue across much of the central and eastern U.S. through Friday and will continue along the East Coast through the weekend, the National Weather Service said Thursday. Temperatures in the high 90s Fahrenheit (30 degrees Celsius) were forecast for the Northeast; Philadelphia and Boston could top 100. Humidity is expected to make it feel even hotter, all but ensuring that sweat will dampen spirits at many celebrations marking 250 years of American independence.

“Anywhere you go in southern New England, you will be dealing with dangerous heat today, tomorrow and Saturday,” said Bryce Williams, a meteorologist with the weather service.

In Boston, entrance to the Boston Pops Fireworks Spectacular will start at 4 p.m. instead of noon on Saturday because of the heat. In Philadelphia, officials shortened the route of a Thursday morning parade, canceled an afternoon all-American Block Party back the start times of an evening picnic and concert at Independence Mall.

In Lower Windsor Township, Pennsylvania, an America 250 celebration including food trucks, games and the highway department's dump truck has been rescheduled for July 8. In Norristown, Pennsylvania, officials canceled a parade set for Saturday, citing the safety of residents, participants and first responders, though evening fireworks and an afternoon party featuring games, food, and music will go on as scheduled.

“The parade is one of our community’s most beloved traditions, and we share in the disappointment of its cancellation, especially as we celebrate America’s 250th birthday,” Interim Municipal Administrator Jayne Musonye said.

Gettysburg National Military Park in Pennsylvania moved outdoor events indoors. Amtrak, meanwhile, canceled some train routes due to the heat Thursday, including the Acela between Boston and Washington, and said others may operate with reduced speeds resulting in delays through Saturday.

A heat dome — high-pressure systems above a region that trap heat and humidity — has been smothering parts of the U.S., from the Midwest to the East Coast. Beyond the holiday festivities, officials in many communities are taking steps to keep residents safe, including opening cooling centers. In Boston, several air-conditioned museums are offering free admission to city residents, and in Providence, Rhode Island, city pools and waterparks have extended their hours.

As the heat bore down on New York, Mayor Zohran Mamdani urged people conserve energy by setting their air conditionings to 78 degrees — a step previous mayors, including former Mayor Rudy Giuliani, have advised — in order to avoid stressing the power grid. Nevertheless, the request drew a round of jeers from the Democratic mayor’s conservative critics online.

Florida Gov. Ron DeSantis, a Republican who pokes at the mayor often on social media, responded on X “Is this what was meant by the warmth of collectivism?,” spinning a phrase the democratic socialist employed in his inaugural address back at Mamdani.

The operators of the electric grids in New York state, New England and one stretching across 13 mid-Atlantic and midwestern states all projected that electricity demand would peak on Thursday before falling back slightly on Friday. They have not issued emergency calls to reduce consumption, however, and industry analysts say system planners prepare for such circumstances.

PJM Interconnection, which operates the grid that serves 65 million people from New Jersey to Illinois, said Thursday’s projected peak would set an all-time high for summer electricity demand, last set in 2006. That peak is well above what PJM had projected it would see this summer, but it said it had a cushion of energy capacity above that peak.