6/28/2026 3:57:00 AM until 6/28/2026 5:00:00 PM

* WHAT...Dangerously hot conditions with heat index values up to 110 degrees possible during the daytime hours. * WHERE...In Delaware, New Castle County. In New Jersey, Mercer, Camden, Gloucester, and Northwestern Burlington Counties. In Pennsylvania, Delaware, Eastern Chester, Eastern Montgomery, Lower Bucks, and Philadelphia Counties. * WHEN...From Wednesday afternoon through Saturday evening. The hottest conditions are forecast to occur Thursday through Friday. * IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events. * ADDITIONAL DETAILS...Very warm low temperatures in the mid 70s to low 80s at night will not offer any relief from the heat. This combined with multiple days of near record breaking temperatures will exacerbate the impacts from the heat and humidity.