Washington D.C. experiences a humid subtropical climate, which includes cold winter periods capable of producing significant snowfall. While the city is not known for deep, persistent snowpack, it regularly receives seasonal accumulations that affect daily life and transportation. The proximity to the Atlantic coast and the movement of cold air masses create a specific meteorological environment conducive to winter precipitation events.
Understanding Typical Snowfall
The average annual snowfall, recorded at Ronald Reagan Washington National Airport (DCA), is approximately 13.7 inches per year. This modest annual total, however, masks a high degree of variability, as some years see minimal snow while others far exceed the average. The number of days with measurable snowfall (0.1 inches or more) is typically around eight per year, meaning most snow events are light accumulations. Winter seasons can range dramatically, from the record low of just 0.1 inches (1973–1974) to the record high of 56.1 inches (2009–2010). This wide fluctuation means residents must be prepared for a spectrum of possibilities, from a nearly snowless winter to a season dominated by multiple large storms.
The Peak Snow Season
The seasonal window for snowfall generally extends from December through March, though measurable flakes can occasionally fall as early as November or as late as April. Statistically, the period of highest frequency and greatest volume of snow is concentrated in January and February. These two months often account for about 75% of the city’s total annual accumulation. Snow events require a specific meteorological setup, often involving a “battle zone” where cold air meets moisture flowing up the coast from the Atlantic Ocean. For snow to fall and accumulate, the temperature profile through the atmosphere must remain below freezing from the cloud base down to the ground. When these elements align, the resulting Nor’easters can deliver substantial snow to the region.
Notable Historic Snowstorms
While the average snowfall is moderate, D.C. has a history of powerful, disruptive winter storms. The city’s all-time record single-storm accumulation occurred during the Knickerbocker Storm in January 1922, which dumped 28.0 inches of snow on the city. This historic event caused severe disruption, including the collapse of the Knickerbocker Theatre roof. More recently, the Blizzard of 1996 delivered 17.3 inches of snow, paralyzing travel across the Northeast corridor. The February 2010 storm, nicknamed “Snowmageddon,” dropped 17.8 inches, contributing to the snowiest winter season on record. These outlier events demonstrate the capacity for extreme snowfall, where one storm can surpass the city’s average annual total.
How Washington D.C. Responds to Snow
When significant snow is forecast, the city mobilizes the D.C. Snow Team to treat the roads. They use pre-treatment with a liquid brine mixture, which is applied to primary and secondary routes to prevent snow and ice from bonding to the pavement surface. The Department of Public Works prioritizes major commuter thoroughfares and designated Snow Emergency Routes first, with residential streets being cleared simultaneously by smaller plows.
Federal and Transit Response
The impact of heavy snow extends to the federal government, where the Office of Personnel Management (OPM) makes the final decision on the operating status for federal offices inside the Capital Beltway. OPM’s announcement considers weather forecasts, traffic conditions, and public transit status, dictating whether federal employees face closures, delayed arrivals, or mandatory telework.
The Washington Metropolitan Area Transit Authority (WMATA) implements a severe weather plan, which may involve modifying or suspending Metrobus service due to poor road conditions. While Metrorail can operate close to normal with up to six inches of snow, above-ground service may be suspended if accumulation reaches eight inches or more for safety reasons. Local airports often experience dozens of cancellations and delays, sometimes requiring temporary runway closures for snow clearing operations.