Snowfall in the nation's capital

 

January 2016 snowfall, Bethesda, Maryland

It's no secret that snowfall has been a scarce in the nation's capital for the last couple of years.  That's part of a more than decade-long trend now below average snowfall.  Washington, D.C. averages 13.7" of annual snowfall, according to NOAA.  That's based on NOAA's running 30-year average which is updated every decade.

The current 30-year average was updated in 2021 to reflect the period of 1991-2020 replacing the previous data set of 1981-2010.  One of the most notable trends when DC's data set was updated was how DC's average annual amount of snow decreased from 15.4" from 1981-2010 to 13.7" for the current 1991-2020 data set.  Essentially, the decade of the 2010s replaced the 1980s and Washingtonians saw noticeably less snow in the 2010s than the 1980s.

There were some notable exceptions to this with four snowier than average winters over the last decade; most notably 2013-2014 (32.0").  DC's last snowier than average winter, however, was in 2018-2019 (16.9").  The nation's capital has had only one snowier than average month since then with 12.3" in January 2022.  There hasn't been a snowier than average February in the nation's capital since 2015 (9.8") or March since 2018 (4.5"). 

It's worth noting that March is the only month DC's snowfall average has increased over the last decade (from 1.3" in 1981-2010 to 2.0" from 1991-2010).  That's because March was DC's snowiest month of the year four times between 2011 and 2020. 

December has also had a discernable snowfall trend in the nation's capital with only one snowier than average December (2017) over the last decade.  Consequently, DC's December snowfall average declined from 2.3" (1981-2010) to 1.7" (1991-2020).  December used to be D.C.’s third snowiest month of the year, but has since been replaced by March.  March has been the only month in the last decade that Washingtonians had above average snowfall with any regularity, with five such occurrences since 2011.

What helps this December stand out is that for the first time since 2019, the nation's capital had accumulating December snowfall.  Although only 0.1" accumulated at National Airport on December 11, a daily record of 0.5" occurred at Dulles Airport and that's more snow than it saw all of last winter.  It's too early to tell whether or not this snowfall will be a harbinger of things to come this winter.  My colleagues and I on the WUSA9 Weather Team think the 2023-2024 winter will be snowier than average in large part to the presence of El Nino for the first time since 2018-2019.