What’s in store for the Philadelphia region this winter? The NBC10 First Alert Weather team unveiled their winter weather outlook for 2025-2026. When is winter? Winter begins on Sunday, Dec. 21, 2025, and lasts until Friday, March 20, 2026. What will winter be like in the Philadelphia region? We’re expected to see slightly more snowfall than average but also milder temperatures at the start of winter in December and early January. We’ll then see normal snowfall amounts and colder, more average temperatures in February and March. Forecast from the Climate Prediction Center According to the National Weather Service’s Climate Prediction Center, temperatures will be slightly above average this winter in the Philadelphia region and surrounding suburbs. The cold air this winter will stay locked in the northwest part of the country while the southwest will be warmer than normal. As far as precipitation, the Climate Prediction Center believes the Philadelphia region will see a normal amount of snow and rain this winter. What is La Niña? La Niña is a weather pattern across the Pacific Ocean in which strong winds blow warm water at the ocean’s surface from South America to Indonesia. As the warm water moves west, cold water from the deep rises to the surface near the coast of South America. How will La Niña impact the winter weather in the Philly region this year? The Climate Prediction Center believes there will be a weak La Niña for the Philly region this winter. Under a weak La Niña, the Philadelphia area will have a slightly above average amount of snowfall. What is the North Atlantic Oscillation? The North Atlantic Oscillation (NAO) Index shows changes in the strength of two recurring pressure patterns in the atmosphere over the North Atlantic Ocean. A positive NAO – anywhere above zero – indicates milder and less stormy conditions while a negative NAO – anywhere below zero – indicates a stormier track. What does the NAO show for the Philly region this winter? The NAO shows stormier conditions for the end of November and then milder conditions for the first full week of December. The NAO then shows stormier conditions in the middle of December towards Christmas. It’s during that time period that the Philly region could be seeing more significant storms and colder air. The NAO shows the milder conditions will return after Christmas into the new year. Download the NBC10 app and follow the NBC10 First Alert Weather team to get the latest weather updates. ...read more read less