Unusually Dry and Warm December

 

NOAA's 6 - 10 Day Temperature Outlook

December has gotten off to an unusually warm start in the Nation’s Capital.  There were six days with highs of at least 60° at National Airport, compared to only three days when temperatures fell to 32° or colder.  Temperatures for the first two-thirds of the month were 5.6° warmer than average.

Nine of the last 10 Decembers were warmer than average in Washington, D.C.  What’s made this month unusual is how warm the first few weeks of December have been.  For the first time since 2015 Washingtonians enjoyed 70° warmth not once but twice this month.  Two record high-low temperatures were also set at National Airport.  NOAA’s day temperature outlook calls for an above average chance for more warmer than normal temperatures in the D.C. Metro Area through December 30.

This month has also been drier than average, with only 0.17” of rain as of December 20.  That’s not good news for the Nation’s Capital following a drier than average October and November.  A total of 4.42” of rain fell in Washington, D.C. since October 1, or less than half of average for that time. Consequently, the latest Drought Monitor Index shows “Abnormally Dry” conditions for much of central Maryland and Virginia, including the District of Columbia.  While the Nation’s Capital has a rainfall surplus of 2.93” for 2021 as a whole, the three-month period dating back to October 1 has been unusually dry. 

NOAA’s Climate Prediction Center expects “Near Normal” rainfall in the Nation’s Capital through the end of the year.  However, that wouldn’t be enough to prevent this month from finishing as one of D.C.’s driest on record.  This combination of warm and dry weather isn’t good news for D.C. Area winter weather enthusiasts hoping for a White Christmas.  La Nina winters, such as this one, often feature near to slightly warmer than average temperatures with near to slightly drier than average conditions in the Nation’s Capital.

D.C.’s Driest December’s  (Source: NOAA)

1.  0.19” (1889)
2.  0.22” (1953)
3.  0.30” (1898)
4.  0.47” (1965)
5.  0.50” (2017)
6.  0.65” (1980)
7.  0.71” (1937)
8.  0.85” (1979)
9.  0.97” (1873)
10.  1.07” (1925)