The heat wave shattered temperature records, led to more emergency room visits, and created serious risks for millions of people preparing to spend the Fourth of July outdoors, Anadolu Agency reported.
More than a dozen places in the Mid-Atlantic and Northeast either matched or broke their record high temperatures for Friday, including Washington, DC.
The city reached 39C (102F), exceeding the previous record of 38C (101F) set in 1872.
By Saturday, the worst of the heat is expected to move slightly south, though Washington, DC, is still forecast to reach 39C (102F).
That would make it the hottest Fourth of July ever recorded in the city.
Philadelphia and New York City are also expected to approach 38C (100F), with heat index values near 41C (105F).
Several holiday events were canceled or postponed because of the extreme heat.
Washington, DC, canceled its Fourth of July parade planned for Saturday morning, while President Donald Trump’s Great American State Fair delayed its opening by two hours, moving it to noon.
Philadelphia also called off its Friday Independence Day parade, which had been expected to be among the largest in the country over the holiday weekend, with participants from all 50 states.
In the New York metro area, thousands of Con Edison customers lost power on Friday.
The utility said some outages were intentional shutdowns meant to prevent longer-lasting disruptions. Earlier in the day, voltage reductions were also reported in parts of Staten Island, Queens, the Bronx, Brooklyn and Westchester, according to Con Edison spokesperson Jamie McShane.
A World Weather Attribution analysis found that the combination of extreme heat and humidity seen this week would have been “virtually impossible” without the influence of fossil fuel pollution.