The annual Independence Day parade in Washington, D.C., was cancelled on Saturday, and the opening of the Great American State Fair on the National Mall was delayed, as a punishing heat wave gripped the central and eastern United States.

At least seven people who attended the fair on Friday required advanced life support, according to medical sources cited by CNN. Organisers said the decision to cancel the parade was taken after the National Weather Service issued an extreme heat warning, with heat index values forecast to reach 110–115°F (43–46°C). The fair, a centrepiece of the White House-backed “Freedom 250” celebrations, was temporarily closed on Friday and reopened at noon on Saturday, two hours later than planned.

Despite the conditions, President Donald Trump’s evening address and a fireworks display remained scheduled. The president has promised a “really long” speech at 9:45 p.m., and military flyovers—including a planned nighttime afterburner pass by a B-1 bomber—were still set to proceed, according to event organisers. It was not immediately clear whether the heat would force further adjustments to the programme.

The extreme weather, which US forecasters attribute to a “heat dome” of high pressure trapping hot air, placed more than 197 million people from Kansas to Maine under heat warnings. The strain on power grids prompted PJM, the largest US grid operator serving 67 million customers, to urge conservation. In New York, utility Con Edison reported that approximately 17,000 customers were without electricity by Friday evening. Western media have noted that the 250th anniversary celebrations are unfolding against a backdrop of acute political polarisation, and on the eve of Independence Day, Trump used a speech at Mount Rushmore to warn of a “revival of the communist threat.”

As of Saturday morning, the parade cancellation and fair delay were the only confirmed disruptions to the official programme. The situation remained fluid, with authorities monitoring temperatures and grid stability.