For the third consecutive day Philadelphia reached a temperature record when the official reading hit 95, matching the high for Sept. 6, 1988.
Wednesday's 95 was a a new high for the date, and Tuesday's peak reading at Philadelphia International Airport, 93, tied a record.
Meanwhile, the city confirmed that a heat-related death had occurred last Wednesday, only the third of a summer that has been among the warmer ones on record.
"Drug intoxication" also was a factor in the death, said Health Department spokesman James Garrow.
As in the past two days, Philadelphia public schools closed at noon.
While the cold front will bring lower temperatures, it will still be muggy Friday, when the high is forecast to be 79 with dew points in the uncomfortable 70s.
The weather service forecast discussion says the weekend is looking "unsettled," with chances of showers and thunderstorms throughout, as well as for the start of the work week.