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Philly Records 99-Degree Heat, Breaking Record for the Date

Strategic Insights

— 2 min read

The Philadelphia region has seen a severe heatwave, with temperatures soaring to 99 degrees on Monday, breaking the record for the date. The heat has been exacerbated by high humidity, making it feel like 110 degrees in some areas. However, health experts believe that a storm system that developed on Sunday may have saved lives by pushing back the start of the heatwave. The National Weather Service has issued a warning for potentially dangerous "extreme heat" through Wednesday, but some relief is expected by Thursday, with cooler temperatures predicted for Friday.

Key Takeaways:

  • The official temperature in Philly hit 99 degrees on Monday, breaking the record for the date, which was previously 98 degrees set in 2024.
  • The heat index was forecast to be around 105 degrees on Tuesday, with Philadelphia having a good chance of reaching 100 degrees for the first time since 2012.
  • The air is so humid that it is capable of sabotaging the body's cooling system, making it difficult for people to stay cool.
  • Temperatures may struggle to drop below 80 degrees at night, which is especially dangerous for people without air-conditioning.
  • The Sunday storm system that developed on the periphery of the high-pressure dome may have saved lives by pushing back the start of the heatwave.
  • Heat-related mortality is dependent on duration, and the shorter the heatwave, the better for saving lives.
  • Philadelphia's heat-response plan, developed in the 1990s, includes opening cooling centers and nudging people to check on older neighbors.
  • The Philadelphia Corporation for Aging's Heatline will be operating on Tuesday and Wednesday to help people stay cool and safe.
  • Heat-related deaths have decreased dramatically in Philadelphia, with an average of about four deaths per year since 2013, compared to an average of about 40 deaths per year in the 10-year period that ended in 2002.

Statistics:

  • 99 degrees: the official temperature in Philly on Monday, breaking the record for the date.
  • 105 degrees: the forecast heat index for Tuesday.
  • 2012: the last time Philadelphia reached 100 degrees.
  • 1907: the year Philadelphia's 100-less streak ended.
  • 99 degrees: the record high for a June 24, set in 1923.
  • 40: the average number of heat-related deaths per year in the 10-year period that ended in 2002.
  • 4: the average number of heat-related deaths per year since 2013.
  • 215-765-9040: the phone number for the Philadelphia Corporation for Aging's Heatline.
  • 8:30 a.m. to 8:30 p.m.: the operating hours of the Heatline on Tuesday and Wednesday.

Sources:

  • The Philadelphia Inquirer, June 23, 2025
  • National Weather Service
  • AccuWeather Inc.
  • Temple Health-Chestnut Hill Hospital Emergency Department
  • Philadelphia Corporation for Aging
  • Health Department
  • Tribune Content Agency, LLC

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