Extreme heat has disrupted Fourth of July celebrations across parts of the US, including the cancellation of a parade in Washington, DC.
The Great American State Fair in the nation's capital - marking the country's 250th birthday - was also temporarily shuttered after multiple people were treated for heat-related illnesses.
More than 165 million people were sweltering on Friday under record temperatures along the US East Coast and Midwest, according to the US National Weather Service.
The heatwave is disrupting the holiday weekend as President Donald Trump hosts a celebration marking America's 250th birthday and multiple World Cup matches take place outdoors.
The 4 July holiday is traditionally characterised by lots of outdoors activities - barbecues in yards and on rooftops, community parades and fireworks at night.
But multiple events commemorating the American holiday - and the country's 250th birthday - were cancelled due to the blistering heat, from New Jersey, Pennsylvania and Maryland to as far west as Colorado.
Among the cancelled events on Friday was Philadelphia's Salute to Independence Semiquincentennial Parade, which was slated to be one of the biggest events across the US.
"As much as this decision pains everyone inside our organisation, we simply cannot host an event of this size and scale under these dangerous heat conditions," Michael DelBene, the CEO of parade organiser Wawa Welcome America, said in a statement to the BBC.
In Washington, an Independence Day morning was cancelled "after extensive and careful consideration of the safety of our participants, spectators, and staff as the top priority," organisers said.
The intense heat also led to the closure of the fair on the National Mall for several hours on Friday, one day before the holiday. The State Fair reopened at 17:00 local time (22:00 BST) after conditions improved, the organiser, Freedom 250, said.
"The safety and wellbeing of our guests, volunteers, performers, vendors, and staff is our highest priority," the event organisers said.
The DC Fire and EMS Department treated several people for "heat-related illnesses" at the fair on Friday, a spokesperson for the department told BBC News. He said these were caused by "record-breaking temperatures" at the event.
At least 11 people were taken by ambulance from the fair, the spokesperson said, but did not elaborate if all were heat-related injuries.
"It is going to be a very busy weekend," a spokesperson for the DC Fire and EMS Department told the Washington Post. "We know that there are going to be heat-related illnesses on and off the Mall, and we encourage our residents and visitors to take precautions if you're going to be out in the heat."
Robin Ardito, who attended the fair, said she saw a middle-aged woman who appeared to be suffering from a heat-related illness. The woman was being tended to by fair staff with both hands in buckets of ice, Ardito said.
"It was too hot to be holding an event like this," she said.
Another event in Washington DC was impacted when US Capitol Police delayed public entry for Friday evening's outdoor A Capitol Fourth concert from 15:00 local time (19:00 GMT) to 19:00 local.
Trump is expected to speak outside at a 4 July celebration on Saturday, despite the predicted high temperatures. The president has maintained that he wanted to gather outside for the celebration.
"I'm gonna make a really long speech just to show that I can do anything," he said.
The extreme heat was expected to continue through the weekend as the hottest spell of the year so far sends the mercury soaring to levels not seen, in some areas, in decades.
It follows an unprecedented spell of early summer heat across Europe, with record highs across the continent.
Searing heat and high humidity is not unusual across North America.
But the widespread nature of this event, across central and eastern areas on Friday and then the east for the weekend, sets it apart as potentially dangerous.
Philadelphia and Washington DC are expected to reach 104F (40C) and 103F with the humidity making it feel like 112F and 111F , respectively, approaching their all-time record highs, according to the NWS.
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On Thursday, New York City hit 100F (38C) degrees, its hottest day since 2012, and the heat index remains at triple digits again on Friday.
"These are extremely dangerous conditions," said New York City Mayor Zohran Mamdani.
Saturday might see the heat breaking in some central areas, but not in the east where it will be dangerously hot for those at outside events.
The other concern is severe thunderstorms on the northern plains, the Midwest and across to the Great Lakes. These will bring a dramatic end to the heat with damaging hail, destructive winds, flash flooding and even a few tornadoes.
By Sunday the heat will intensify in Virginia, the Carolinas and the southeast before building in western parts of the USA and Canada into next week.
Parts of Canada, including southern Ontario have already reached mid-30sC (over 90F) this week.
Heatwaves have become more frequent, more intense, and last longer because of human-induced climate change. The world has already warmed by about 1.1C since the industrial era began and temperatures will keep rising unless governments around the world make steep cuts to emissions.
