A person cools off with water from an open fire hydrant during a heat wave on the West Side of Chicago on July 2, 2026. Octavio Jones/AFP via Getty Images
Blistering heat forced organizers across large parts of the Midwest and East Coast to cancel or delay July Fourth celebrations on the eve of the holiday.
America’s Independence Day Parade in downtown Washington was canceled as the heat index was expected to reach 110 to 115 degrees.
Washington saw a large fair along the National Mall closed temporarily amid the conditions, while Philadelphia canceled its main Independence Day parade. A township in New Jersey ended its annual procession, and shows in upstate New York, along with a delayed Boston fireworks display, were among those affected.
The cancellations came as the largest U.S. power grid operator ordered customers in emergency electricity-reduction programs to curtail usage as a heat wave drove demand toward a 20-year record high.
PJM Interconnection, which serves 67 million people, triggered the alert as generator outages plagued the grid. PJM faced overloaded transmission lines and surging air-conditioning demand, according to the organization. The measures focus on industrial and residential users with contracts that compensate them for slashing consumption during emergencies.
“The alert was issued to increase reserves on the system and avert outages during peak demand around 6 p.m. EDT on Friday,” PJM stated.
Demand closed in on the all-time peak of 165.6 gigawatts, which was set two decades ago, as PJM’s peak load on Thursday was about 163 gigawatts.
U.S. Energy Secretary Chris Wright issued emergency orders earlier in the week to help stabilize PJM’s service region ahead of the heat wave.
“Maintaining affordable, reliable, and secure power in the PJM service territory is non-negotiable,” Wright said in a statement. “The previous administration’s energy subtraction policies weakened the grid, leaving Americans more vulnerable during events like this. Thanks to President [Donald] Trump’s leadership, we are reversing those failures and using every available tool ensuring Americans in the Mid-Atlantic have continued access to affordable, reliable, and secure energy to power and cool their homes.”
PJM has been addressing surging demand from data centers and electric vehicles, which had been overloaded prior to this week’s extreme heat. Virginia, within PJM’s footprint, leads the nation with 398 operating data centers and hundreds more set to be built.
The grid operator issued a hot weather alert through Saturday, extended through Sunday in key zones that include the world’s largest concentration of data centers.
One Department of Energy order permits the reduction of power from data centers and other large customers with backup generation as a last resort ahead of voltage reductions or outages. A second order temporarily loosens certain environmental permit restrictions for power plants through July 3.
PJM anticipates demand that would top the previous summer record. The grid operator is running at maximum generation, managing loads, and low-voltage alerts to increase available supplies by postponing maintenance and preparing demand-response resources.
PJM’s reliability through the summer has been flagged in assessments by the North American Electric Reliability Corporation.
The National Weather Service has warned of heat-related illnesses as the region faces temperatures potentially reaching 105 to 115 degrees Fahrenheit. PJM is seeking to prevent rolling blackouts or deeper voltage reductions as Americans crank up air conditioners.
No outages were reported Thursday despite near-record demand and a sudden drop in generation capacity that required expensive peaker plants to activate.
Reuters contributed to this report.
