2019 Picks Up Where 2018 Left Off

DC had a fitting end to 2018 with a warmer and wetter than average December.  Last month finished 3.8° warmer than average for the seventh time in the last eight years.  A total of 5.82” of rain also occurred in DC last month, which made for DC’s eighth wettest December on record.  2018 finished with 66.28” of rain – DC’s wettest year on record!

January 2019 has gotten off to a similar start, with above average temperatures and forecasts of rain in the DC Metro Area.  Average January temperatures in Washington, D.C. feature a high/low of 44°/29° on January 1.  DC’s warmest January temperature on record is 79° on January 26, 1950.  Although uncommon, temperatures in the 70s occur much more frequently in the Nation’s Capital during the month of January compared to subzero temperatures.  The last time DC had a January high temperature in the 70s was on January 6, 2017 (73°).

Meanwhile the coldest January temperature observed in the Nation’s Capital is -14° on January 1, 1881.  DC’s coldest January temperature at National Airport is -5° on January 17, 1982.  The last time Washingtonians experienced a below 0 temperature was on January 19, 1994 (-4°). Eleven of the last 20 January’s have been colder than average in DC, including four of the last five.  Area residents should recall the frigid start to 2018 with high temperatures in the 20s on six of the first seven days.

The month of January averages 2.81” of rain in Washington, D.C. (that includes 5.6” of snow).  However, 15 of the last 20 January’s have been drier than average in the Nation’s Capital, including the last three.  It’s possible to have a drier than average month, and still have a snowier than average month.  For example, January 2016 finished with 2.68” of rain (that includes liquid snow equivalent), but a record snowstorm occurred on January 22-23, 2016 when a total of 17.8” fell (DC’s fourth largest snowfall).  That’s possible when a dry snow occurs.  

When temperatures are near freezing, the atmosphere can hold additional water vapor leading to snow that has a higher moisture content.  The colder the temperatures are, the lighter and drier the snowfall tends to be.  NOAA expects the warmer than average temperatures with near average precipitation to continue in the DC Metro Area through the middle of January.