Philadelphia, PA – September 2025 closed out as one of the warmest and driest months in recent memory across Pennsylvania, New Jersey, and Delaware, according to the National Weather Service in Mount Holly. For inland areas, it marked the warmest September in roughly 10 years.
According to the NWS report, coastal locations stayed closer to normal temperatures thanks to onshore winds, but inland cities such as Philadelphia, Reading, and Allentown experienced well above-average heat. Philadelphia recorded an average September temperature of 73.0°F, which was 3.1°F above normal.
Rainfall was significantly below average across much of the region. Mount Pocono recorded just 1.23 inches of rain, making it the seventh driest September since records began in 1901, and more than 4 inches below normal. Other major cities also saw deficits, including Allentown at 2.66 inches (-2.18 inches) and Philadelphia at 1.79 inches (-2.61 inches).
The exception was along the immediate coast, where rainfall totals came closer to seasonal averages. Atlantic City International Airport, for example, logged 4.36 inches of rain, slightly above normal.
Despite the overall dry conditions, forecasters noted the region is in better shape compared to last September, when a developing drought began to take hold.
