The third - and most-intense - heat wave of the year is underway, and the National Weather Service has issued an "excessive heat warning" for the next two days.
Temperatures will not threaten any records, but it will feel as if it's 100 degrees in the city and nearby suburbs, the hottest it's been so far this year, the weather service says.
Weather watchers based in Mount Holly say residents of Philadelphia and nearby communities also face nighttime temperatures that won't fall much below 80.
Monday should feel almost as hot as Sunday. Temperatures are also likely to top 90 on Tuesday and Wednesday.