In the early going, the temperature rise has been capped somewhat by cloud cover and some ealry-arriving showers.
But the dewpoints have shot upward, meaning the air is filling with moisture, not to mention discomfort, and the National Weather Service is saying the heat index could shoot past 110 in parts of South Jersey.
But by day's end, thunderstorms could trump the heat in terms of the public's attention.
The Storm Prediction Center, in Oklahoma, has placed just about the entire region under a "moderate" risk of severe thunderstorms.
To qualify, a storm has to pack wind gusts of 58 m.p.h., and the storm center says chances are about 50-50 that those winds will materialize when the storms show up later this afternoon.
This summer, it seems that the storms have been prone to snub the immediate Philadelphia region, and that could well be the case again today.