A prolonged and dangerous heatwave will intensify across a swathe of the US this week, ushering in scorching daytime heat, high humidity and stifling overnight temperatures, forecasters predict.
Some 120 million people nationwide are under an extreme heat warning as of Tuesday, as Americans head into the Fourth of July holiday weekend, the National Weather Service (NWS) said.
To the north, much of Canada began experiencing its own heatwave on Tuesday, with temperatures up to 37C (99F) expected in Ontario.
It comes after Europe's unprecedented early summer heatwave scorched several countries over recent days, with temperature records broken across the continent.
The heatwave is forecast to hit a large area of the country, from the US east coast to central areas of the country. Starting on Thursday, about 250 million people will be exposed to some dangerous level of heat, according to weather forecasters.
The extreme temperatures caused by a heat dome, will peak in the Midwest and Mississippi Valley by Thursday, the NWS predicted.
It will shift east into the Ohio Valley and East Coast on Thursday and into the holiday weekend, according to the weather service.
Temperatures ranging from 95F-105F combined with high humidity will bring the heat index to 100F-115F.
Daily temperature records are expected to be broken on Thursday and Friday, with some monthly and all-time records possible.
Officials are warning people living in the affected areas to limit time outdoors, stay hydrated and ensure access to air conditioning or cooling centres.
New York City Mayor Zohran Mamdani activated a heat emergency plan with hundreds of cooling centres set to open across the city on Wednesday.
Detroit, Michigan, where temperatures could reach 100F, opened a dozen recreation centres with air conditioning for residents to cool down.
With the intense weather, some World Cup matches could have heat indexes exceeding the threshold where global players' union Fifpro considers conditions to be too unsafe for play.
The hottest weather will be in Texas, which will mostly hit fans travelling to and from the air-conditioned stadiums in Houston and Arlington.
This may also be the case for the England v DR Congo match on Wednesday in Atlanta, Georgia.
Philadelphia, meanwhile, is moving parts of its Fifa World Cup Fan Festival into cooled tents on Thursday and Friday.
In Canada, temperatures were expected to remain high until Thursday, particularly in the province of Ontario, where it could hit 37C (99F) this week.
Amid the heat, Toronto is due to host a World Cup game on Thursday - when temperatures are predicted to reach 35C (95F).
The country has issued orange heat warnings - the second level of a three-tier alert system - in Ontario.
Meanwhile, central and eastern parts of Ontario, including Montreal, are also predicted to see high temperatures. Yellow heat warnings, the lowest level, are in place.
-BBC
Some 120 million people nationwide are under an extreme heat warning as of Tuesday, as Americans head into the Fourth of July holiday weekend, the National Weather Service (NWS) said.
To the north, much of Canada began experiencing its own heatwave on Tuesday, with temperatures up to 37C (99F) expected in Ontario.
It comes after Europe's unprecedented early summer heatwave scorched several countries over recent days, with temperature records broken across the continent.
The heatwave is forecast to hit a large area of the country, from the US east coast to central areas of the country. Starting on Thursday, about 250 million people will be exposed to some dangerous level of heat, according to weather forecasters.
The extreme temperatures caused by a heat dome, will peak in the Midwest and Mississippi Valley by Thursday, the NWS predicted.
It will shift east into the Ohio Valley and East Coast on Thursday and into the holiday weekend, according to the weather service.
Temperatures ranging from 95F-105F combined with high humidity will bring the heat index to 100F-115F.
Daily temperature records are expected to be broken on Thursday and Friday, with some monthly and all-time records possible.
Officials are warning people living in the affected areas to limit time outdoors, stay hydrated and ensure access to air conditioning or cooling centres.
New York City Mayor Zohran Mamdani activated a heat emergency plan with hundreds of cooling centres set to open across the city on Wednesday.
Detroit, Michigan, where temperatures could reach 100F, opened a dozen recreation centres with air conditioning for residents to cool down.
With the intense weather, some World Cup matches could have heat indexes exceeding the threshold where global players' union Fifpro considers conditions to be too unsafe for play.
The hottest weather will be in Texas, which will mostly hit fans travelling to and from the air-conditioned stadiums in Houston and Arlington.
This may also be the case for the England v DR Congo match on Wednesday in Atlanta, Georgia.
Philadelphia, meanwhile, is moving parts of its Fifa World Cup Fan Festival into cooled tents on Thursday and Friday.
In Canada, temperatures were expected to remain high until Thursday, particularly in the province of Ontario, where it could hit 37C (99F) this week.
Amid the heat, Toronto is due to host a World Cup game on Thursday - when temperatures are predicted to reach 35C (95F).
The country has issued orange heat warnings - the second level of a three-tier alert system - in Ontario.
Meanwhile, central and eastern parts of Ontario, including Montreal, are also predicted to see high temperatures. Yellow heat warnings, the lowest level, are in place.
-BBC
