Spring Gets Off to a Cool and Wet Start in the Nation's Capital

NOAA's Precipitation Outlook for the Final Week of March

Although spring officially arrives in March, this month often feels more like winter in the Nation’s Capital.  March 2019 was no exception, with accumulating snow on March 1 followed by colder than average temperatures on nine of the first 10 days of the month.  That was followed by a stretch where temperatures were above average on six of the subsequent 10 days through March 20.  This has produced a monthly average temperature (combining daily high and low temperatures) 0.5° cooler than average at National Airport (DC’s official weather reporting site).

Including yesterday’s drenching rainfall, there have been 10 days with precipitation so far this dreary month.  The 1.96” of rain yesterday was DC’s highest daily rainfall total since December 15 (2.55”).  Dulles Airport experienced a record 2.69” of rain, more than double the previous March 21 rainfall record of 1.29” from 2000.  It was also the largest daily rainfall total on record during the month of March at Dulles Airport.  With yesterday’s rain, DC has had 3.87” of rain since March 1 (greater than the average of 3.48” for the entire month).  Although Washingtonians had a chilly and wet first full day of spring yesterday, it pales in comparison to what DC residents had a year ago.

DC residents experienced the largest snowfall of the 2017-2018 winter season on March 21, 2018, when a total of 4.1” of snow fell at National Airport.  Although accumulating snowfall is less common in March, DC averages 1.3” of March snowfall.   March has also been DC’s snowiest month in four of the last seven years.  Including the 0.3” of snow on March 1, 2019, Washington, D.C. has had measurable snowfall in seven consecutive March’s – the longest such streak on record. 

NOAA keeps weather records for the United States and updates its climate averages by decade.  The 1.3” March snowfall average in the Nation’s Capital is based on NOAA’s 30-year average for the period from 1981-2010.  While NOAA uses a 30-year average to determine temperature and precipitation information, they are updated every decade.  That means at the end of 2020, NOAA will update its 30-year average to use weather data from 1991-2020.

Temperatures have also shown an interesting trend in the Nation’s Capital in recent years.  While DC residents experienced the warmest and fourth warmest March’s on record in 2012 and 2016, March 2013 – March 2015 were each colder than average.  That was the first time since 1992-1994 that DC had at least three consecutive colder than average March’s.  March 2018 was significant for being DC’s first cooler and drier than average March since 2013.  Meanwhile, this month will finish with near average temperatures and an increased potential for drier than average conditions, according to NOAA’s outlook for March 27 – 31.