A deadly multi-day heat wave tightened its grip on the eastern United States on Friday, breaking records, sending people to the emergency room and increasing the risk for millions of people who are starting to celebrate the Fourth of July outdoors.
More than a dozen places in the Mid-Atlantic and Northeast broke or set high temperature records for Friday, including Washington, D.C. The capital reached 102 degrees, surpassing the record of 101 degrees set in 1872.
On Saturday, the worst of the heat will move a little further south, remaining high for D.C. with a forecast high of 102 degrees, making it the hottest Fourth of July in the city’s history. Temperatures in Philadelphia and New York are expected to be around 100 degrees and the heat index is around 105.
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• Heat-related illnesses and deaths: A 68-year-old man died after trimming bushes on July 2 in Bethel Township, Pennsylvania, where temperatures topped 100 degrees, the Berks County coroner’s office told CNN. The cause of death was a heart attack from overexertion “due to heat exhaustion,” the department said. Meanwhile, the CDC reported Thursday that there are “extremely high levels of heat-related illnesses” in regions of the Northeast.
• Events canceled or postponed: The Fourth of July parade scheduled for Saturday morning in Washington, D.C., was canceled due to extreme heat in the nation’s capital. President Donald Trump’s Great State Fair opens two hours later at 12 noon. In Philadelphia, the Independence Day parade, which was expected to be one of the largest in the country this holiday weekend, was canceled and included representatives from every state.
• Power outages in New York: Thousands of customers in the New York City metro area were without power Friday, according to local utility Con Edison. Some of the shutdowns have been disabled to prevent extended downtime. Voltage reductions also occurred earlier in the day in parts of Staten Island, Queens, the Bronx, Brooklyn and Westchester, Con Edison spokesman Jamie McShane told CNN.
• Heat wave caused by environmental pollution: The intensity of this week’s heat and humidity would have been “virtually impossible” without the effects of fossil fuel pollution, according to World Weather Attribution analysis.
More than 20 cities broke records Thursday, some of them hotter than Phoenix, the southwestern desert city known for its blistering heat. Temperatures will again reach triple digits in the District of Columbia, Philadelphia, Boston and parts of New York on Friday afternoon.
The combination of heat and humidity is making conditions even hotter, and heat index values—what the air actually “feels like” to the body—are predicted to rise even higher than the actual air temperature.
Human-caused climate change is making normal summer weather much more dangerous. The intensity of the heat and humidity this week would have been “virtually impossible” without the effects of fossil fuel pollution. The results were released early Friday by World Weather Attribution, a science network that analyzes the role of climate change in causing extreme weather events.
Heat is the deadliest weather hazard in the United States, and high humidity increases the risk by keeping temperatures elevated and preventing sweat from evaporating effectively, making it difficult to cool the body. Nighttime lows are also hotter now than they were decades ago, making it harder for people to get respite and rest.
The risk can increase quickly, especially for older adults, children, outdoor workers and people without reliable access to air conditioning. Anyone heading outdoors for the holiday weekend should plan to take frequent breaks indoors or at least in the shade. Drink water frequently, avoid strenuous activities, and never leave children or pets in parked cars.
As homes and businesses turn on their air conditioners to keep them cool, the demand for electricity increases.
Energy Secretary Chris Wright this week directed data centers in the Mid-Atlantic to use backup power instead of electricity from the public grid, in part to ensure there is enough of it to power residential air conditioning systems.
Wright’s orders on Tuesday were directed to data centers and other large electricity consumers served by PJM, the nation’s largest electric grid operator. The PJM region consists of 13 states. Virginia is home to the world’s largest cluster of data centers, and their soaring energy demand has led to major spikes in electricity prices in some mid-Atlantic states over the past couple of years.
Outside of PJM’s grid, more than 19,000 Con Edison customers in the New York metro area and upstate lost power Thursday, according to the utility’s outage map.
“Heat, humidity and increased demand for electricity to power air conditioners” are putting additional strain on Con Edison’s system, primarily in the Bronx and Queens, the company said in a press release Friday. “Con Edison teams have restored service to more than 60,000 customers affected by isolated outages since the heat wave began.”
Mayor Zohran Mamdani posted a message on X asking residents to set the AC temperature to 78 degrees and turn off electrical appliances to save electricity and reduce the load on the grid.
Many cities, including Boston, New York, Philadelphia, Washington, D.C., and Raleigh, North Carolina, are opening cooling centers and expanding public resources as dangerous heat sets in.
Washington, D.C., has activated a heat warning through July 5 and is expanding cooling centers, hydration stations and emergency medical resources as hundreds of thousands of visitors flock to the nation’s capital for holiday activities. Organizers of the National Mall celebration are adding drinking water stations, cooling tents and air-conditioned buses for participants.
Hundreds of cooling centers have opened in New York City and mobile medical vans have been deployed to deliver water, sunscreen and health screenings. More than 2,200 LinkNYC kiosks provide directions to the nearest cooling center.
Philadelphia has declared a heat emergency until Sunday evening. A ceremony featuring a live virtual address from the pope was moved indoors and officials cut hours for the city’s World Cup fan festival ahead of Saturday’s match between Paraguay and France. Event organizers also canceled Fourth of July and World Cup parties.
Since July 2, Amtrak has canceled at least 26 trains in the Northeast, including trains serving major East Coast cities such as Baltimore, Philadelphia, New York and Boston. These cancellations are due to “temperature-related conditions,” Amtrak noted in posts on X.