Philadelphia heat wave to send temps near 100 degrees
A Heat Health Emergency has been declared in Philadelphia, where temperatures could break a record set in 1923 amid an early summer heat wave.
Record-challenging heat is heading to the Northeast. AccuWeather’s Ali Reid is in Philadelphia covering the dangerous heat wave.
A massive heat wave is unleashing the hottest weather in years across the eastern United States, and the temperature in one of the biggest cities in the country could hit triple digits for the first time in over a decade.
Philadelphia came one degree shy of hitting the 100-degree mark on Monday afternoon, and the temperature will make a run at the century mark again on Tuesday. The AccuWeather RealFeel® Temperature will be even higher, peaking around 105 F, when factors such as high humidity and intense sunshine are taken into account.
The sun shining over city hall in Philadelphia. (Getty Images)
Extreme heat can be dangerous for people who spend time outdoors. It also puts extra strain on the energy grid as air conditioning units go into overdrive to keep homes and businesses cool.
A Heat Health Emergency has been declared in Philadelphia in response to the heat wave. Cooling centers will be open across the region for those who need access to areas to get relief from the extreme weather.
“The best way to protect our loved ones is to make sure they can get into air conditioning during the hottest part of the day," Health Commissioner Dr. Palak Raval-Nelson said. "As always, we encourage Philadelphians to check on elderly friends and neighbors to make sure they’re safe and don’t need assistance. If you’re worried about someone’s health during the emergency, you can call the Philadelphia Corporation for Aging’s Heatline at 215-765-9040.”
When was the last time it was 100 degrees in Philadelphia?
The last time the temperature reached 100 degrees in Philadelphia was on July 18, 2012.
Tuesday's high of 99 degrees set a new daily record for June 23, topping the old record of 98 degrees set just last year. On Tuesday, the daily record of 99 degrees, set in 1923, is likely to be tied or broken. However, the all-time record of 106 degrees set on Aug. 7, 1918, is not expected to be challenged.
Hidden danger: High temperatures at night
An often overlooked part of heat waves is how warm it remains at night, especially in cities where pavement can retain the heat of the day for hours after the sun has set.
The temperature is forecast to only drop into the low 80s at night early this week in Philadelphia. It is rare for the low temperature to stay in the 80s at night, something that happened only once in all of 2024.
“Extreme heat is tragically the leading cause of weather-related fatalities in America,” AccuWeather Chief Meteorologist Jonathan Porter said. “There is an amplified risk of heat-related illnesses because this is the first heat wave of the year for millions of people, and their bodies are not yet acclimated to this type of heat and humidity."
Over the last 30 years, extreme heat has been the leading cause of all weather-related fatalities in the United States annually, according to the National Weather Service. In 2024 alone, there were 199 heat-related fatalities in the country, more than tornadoes, hurricanes, lightning and cold weather combined (170).
Temperatures in Philadelphia are forecast to retreat from record levels later in the week with highs in the 80s.
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