Heatwaves scorch millions across the East Coast with New York City and Boston seeing highs of over 100F

John F Kennedy International Airport recorded 100 degrees Fahrenheit (38C) at midday on Tuesday for the first time since 2013

Extreme heatwaves scorched parts of the U.S. on Tuesday, including on the east coast, where several major cities including New York and Boston climbed to triple-digit temperatures.

John F Kennedy International Airport recorded 100 degrees Fahrenheit (38C) at midday – the first time since 2013 – according to the National Weather Service, which described conditions as “extremely dangerous.”

The oppressive heat hit the Big Apple as residents headed to the polls to vote in the city’s Democratic primary election for city mayor.

Nearly 40 US cities broke record high marks on Monday, including Philadelphia, Baltimore and Raleigh, North Carolina, which all broke daily heat records with temperatures of 99 degrees (37C), 104 degrees (40C) and 100 degrees, respectively.

The NWS previously predicted dozens more records Tuesday as the peak of the “heat dome” – a weather phenomenon where high pressure in the upper atmosphere acts like a lid, trapping heat and causing extreme temperatures and humidity over a specific area.

John F Kennedy International Airport recorded 100 degrees Fahrenheit (38C) at midday on Tuesday for the first time since 2013 (AP)

More than 150 million people were placed under heat warnings, with very warm overnight lows expected to continue through Wednesday, according to the NWS.

“Every East Coast state today from Maine to Florida has a chance of 100 degree actual temperature,” private meteorologist Ryan Maue, a former National Oceanic and Atmospheric Administration chief scientist, said on Tuesday.

“Getting Maine to 100 degrees is infrequent.”

Also joined New York in the 100F club were Boston and Philadelphia, both of which recorded temperatures matching or exceeding it throughout Tuesday. Similarly, Washington D.C., hit 101F (38.3C) by 2 p.m., according to Accuweather.

People stand on the Brooklyn bridge on Tuesday, as temperatures hit triple figures for the first time since 2013 (AP)

The National Weather Service described the conditions as ‘extremely dangerous’ for those in major cities on the east coast, and issued heat warnings affected over 150 million Americans (AP)

The oppressive heat hit the Big Apple as residents headed to the polls to vote in the city’s Democratic primary election for city mayor (REUTERS)

Amtrak reported delays Tuesday due to speed restrictions caused by the heat on routes that went through Washington, Philadelphia and New York.

Several meteorologists told The Associated Press that the heat wave is especially threatening to residents in those cities due to its arrival early in the summer when people haven’t gotten their bodies adapted to the broiling conditions.

Several meteorologists told The Associated Press that the heat wave is especially threatening to residents in those cities due to its arrival early in the summer when people haven’t gotten their bodies adapted to the broiling conditions (AP)

Elsewhere, two 16-year-old hikers were rescued from a mountain in Jaffrey, New Hampshire, late Monday afternoon, after being overcome by the heat, according to the New Hampshire Fish and Game Department.

They were described as being in and out of consciousness and taken to a hospital.