December 26, 2025
Thom Carroll/for PhillyVoice
The Philadelphia area has experienced one of the coldest Decembers in the last couple decades, with the average temperature around 35 degrees. Above, the frozen Schuylkill River after Philly experienced 14 straight days of sub-freezing temperatures in late 2017 and early 2018.
The Philadelphia area is on track to have the coldest December in 15 years, averaging 35.4 degrees through Christmas with snow in the forecast and below-freezing lows projected in four of the next five days.
Using National Weather Service data, this year's mean temperature is well below the 39.3 degree December average from 2000-2024, and it's set to be the lowest since 2010, when it was a frigid 32.7 degrees during the month.
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So far, the lowest recorded temperature this month was 18 degrees on Dec. 9, and there have been nine days with minimum temperatures of 25 degrees or lower. The high this month was 61 degrees on Dec. 19, and there have been five days with high temperatures at or below 35 degrees.
Decembers in Philly have skewed warmer in recent years. The monthly average temperature was 43.5 degrees in 2023 and 38.5 degrees in 2024. The December average was 40 degrees or higher nine times since 2000, including the warmest average of 51.2 degrees in 2015.
While Monday's rainy forecast calls for a high of 55 degrees, every other day through New Year's Eve will have a high below 40 degrees, according to the NWS forecast.
There's also been some unusually early snow this year. In December 2024, the NWS reported just 0.3 inches for the Philly region, and the previous three years there were only traces of snow, less than the smallest measurable amount, in the month.
The snowstorm that swept through the region on Dec. 14 brought 4.2 inches to Philadelphia International Airport, while parts of Bucks and Chester counties saw more than 8 inches of snowfall.
Friday night's forecast calls for snow totaling less than half an inch. Overnight, a mix of rain, snow and sleet will add another inch or two of accumulation. A wintry mix could linger until about noon Saturday, dropping less than half an inch more. The heaviest snowfall is expected in areas north of Philadelphia.
The NWS says travel conditions on roads in the region will be most impacted Friday evening. The Philadelphia region will remain under a winter weather advisory into Saturday morning.
