D.C. sees coldest mid-October weather in years; snow falls in mountains.

It was the coldest this early in the fall since 2015 and may be even a little chillier Wednesday night.

As the Washington area awoke to its coldest morning of fall so far, snowflakes flew and accumulated in the mountains to the west.

Wednesday morning temperature lows ranged across the 30s areawide as patchy frost formed. Washington dipped to 38, Dulles to 33 and Baltimore to 34. Some pockets north and northwest of the city fell to near or below freezing, including Reston with 32 and Ellicott City with 31. These temperatures occurred despite some cloud cover in the hours leading up to dawn, preventing temperatures from falling further since clouds have a blanketing effect and retain heat near the ground.

This first instance of a low temperature in the 30s in Washington came about 10 days earlier than normal (based on weather observations in the past 30 years). It is the earliest it has been this cold early in the season since 2015. The low of 38 marked the chilliest temperature in the District since March 30, when it was 35.

The cold readings across the D.C. area are the result of a blast of unusually chilly air in the eastern half of the nation for the time of year. Washington and Baltimore are on the periphery of the Arctic blast, with the core of the cold stretching from the Upper Midwest to the South.

https://www.washingtonpost.com/climate-environment/2022/10/19/dc-cold-mid-atlantic-mountain-snow/?