Extreme heat bears down as America 250 celebrations ramp up. Trump heads to Mount Rushmore

The sound of fighter jets on military flyovers reverberated across the nation's capital. In New York City, Mayor Zohran Mamdani delivered his own address on the country’s 250th anniversary and cast America as a nation of contradictions “working each day towards the perfection in which it was conceived.”

“The frontier may be closed, we may have walked on the moon, but the work of fulfilling the values first enshrined in the Declaration of Independence, that work endures, and it belongs to us all," Mamdani said, sitting behind George Washington’s desk at City Hall and surrounded by a diverse group of recently naturalized citizens.

The activity culminates in the main event Saturday, when fireworks will erupt in communities across the U.S., along with backyard cookouts and block parties. Trump will deliver another speech at the National Mall in Washington before what is being billed as a historically massive fireworks show.

But for all the celebrations, there are also serious safety considerations as potentially record heat grips much of the Midwest and East Coast. Officials have warned those celebrating the holiday to stay hydrated and take air-conditioned breaks as needed.

Sky-high temperatures lead to cancellations and adjustments to the festivities

The heat has already affected some of the programming surrounding the holiday.

In Philadelphia, the city's Salute to Independence Semiquincentennial Parade was canceled because of the weather.

In Washington, organizers of the Capitol Fourth concert banned the public from attending a Thursday rehearsal because of the heat. The concert Friday, a staple of Washington's Independence Day traditions, is on, but the gates will open to the public later than usual, at 7 p.m. EDT, an hour before the show. Organizers of celebrations in Washington on Saturday said they were adding water stations along with cooling resources and medical support.

From Boston to Norristown, Pennsylvania and Gettysburg National Military Park, plans were shifting to accommodate the soaring temperatures. Amtrak canceled some trains in the Northeast due to excessive heat that could affect the tracks.

The holiday is unfolding at a unique time in the U.S. The anniversary has served as an opportunity for the country to reflect on its history while also reminding it of the political polarization of the moment.

On a holiday of unity, there is an undercurrent of division

Even the celebrations themselves have not quite escaped the divide.

In New York, Mamdani, a Democrat, did not mention Trump by name, but parts of his speech appeared aimed at the president’s divisive rhetoric.

“For generation after generation, we have been told that when the world has sent its people to our shores, it has not sent its best,” Mamdani said in an apparent reference to an a common criticism from Trump. “Those ideals upon which our nation was built — they are strong enough to endure any authoritarian regime, but only if we reach for them."

Freedom 250, an organization aligned with the White House, has come to rival America250, a bipartisan group founded by Congress a decade ago. Freedom 250 has organized much of the activity in Washington, including the Great American State Fair, which has gained attention for the relatively small crowds it has attracted. America250 is behind the ball drops unfolding in many cities, including New York, and will host a concert in Los Angeles on Saturday.

About 4 in 10 U.S. adults feel “proud” about the country’s 250th anniversary, according to an April survey from The Associated Press-NORC Center for Public Affairs Research. Roughly 3 in 10 said “excited” describes their emotions.

Ahead of the holiday, auto technician Joe Fuqua-Bejarano, in Topeka, Kansas, sized up “what makes us awesome” as a people. It is clearly not the politics, in his view, but rather resilience.

“We’ve just all got to find unity somewhere, whether that’s in laughter or perseverance, and keep everybody cool,” he said from the fireworks stand where he is doing a booming business as a side hustle.

Christina Zhou, a 25-year-old research assistant from Cambridge, Massachusetts, said she would aim to “think about just things that are happening locally.”

“It feels a little bit more like within our own personal control," she said.

Associated Press writers Steve Peoples and Anthony Izaguirre in New York, John Hanna in Topeka, Kan., Michael Casey in Cambridge, Mass., and Calvin Woodward in Washington contributed to this report.