The heat in New York City is expected to surpass 100 degrees Fahrenheit (around 38 degrees Celsius) this week—potentially breaking the record for the hottest temperatures seen in parts of the city since 2012. With the added humidity, the heat could feel more like 110 degrees F (around 43 degrees C), according to the National Weather Service (NWS).

“This is a significant heatwave that people should take seriously, because it’s going to be very hot for an extended period of time,” says James Connolly, meteorologist at the NWS.

The “heat index”—a measure of how temperatures feel, rather than the number on the thermometer—is expected to reach 105 degrees F (more than 40 degrees C) this week and could rise to 110 degrees F (43 degrees C), prompting the NWS to issue an “Extreme Heat Warning” for Wednesday and an “Extreme Heat Watch” for Wednesday night through Saturday. A “warning” means forecasters can predict the weather with higher confidence, such as with winter storm warnings and tornado watches, Connolly says.

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Temperatures in Manhattan’s Central Park, where the NWS has historically collected weather data for the city, haven’t surpassed 100 degrees F since 2012. The hottest day ever recorded in the park was 106 degrees F, or more than 41 degrees C, on July 9, 1936, according to the agency.

The extreme heat, which is being driven by climate change, isn’t exclusive to New York City. Due to a mass of warm air currently centered over Kentucky that is moving East, much of the East Coast will experience soaring temperatures this week, Connolly says. The heat in Philadelphia could reach 104 degrees F (40 degrees C) and Baltimore and Washington, D.C., could be as hot as 103 degrees F (39 degrees C).

The searing heat is expected to stick around through the Fourth of July holiday weekend, too: “It’ll still remain hot. Right now, the question is, how hot it will be,” Connolly says.

For people who plan to celebrate America’s 250th anniversary this weekend, Connolly recommends staying hydrated, hanging out in cool environments, wearing loose fitting clothing and being alert for any signs of heat-related illnesses, such as heat stroke or heat exhaustion. And don’t leave children or pets in cars, he adds. “Be aware, and take this heatwave seriously.”

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