Winter Has Returned

Today and tomorrow will be cold, wet and raw in the DC Metro Area.  Communities north and west of town will see more sleet and freezing rain than inside I-495.  Areas south and east of town will primarily see just rain.  That’s the result of a complex weather pattern with temperatures that aren’t cold enough to support a pure snow event in the Nation’s Capital.  Temperatures were much colder on Saturday and Sunday than they were last week and helped surface temperatures fall, making conditions more favorable for freezing rain.  That’s especially true in areas north and west of town (more specifically areas west of I-81 in Virginia and north of I-70 in Maryland).

The transition back to winter has been marked in the Nation’s Capital.  The first week of February was quite warm with high temperatures of at least 56° on five consecutive days from February 3 – February 8.  Washingtonians experienced a record high of 74° last Tuesday, February 5.  That was DC’s first 70° temperature since November 2 (73°).  It was also DC’s warmest stretch of weather in the first half of February since 2009.

February is DC’s snowiest month of the year on average with six of the top 10 snowfalls on record (such as the February 1899 and 1979 snow events).  However, things have changed in recent decades.  While 12 of the last 20 February’s have been warmer than average in Washington, D.C. only six of the last 20 have featured above average snowfall.  Moreover, six of DC’s 10 warmest February’s have occurred just since 1990.  In fact, 2017 and 2018 featured DC’s warmest and third warmest February on record.  That illustrates that while the right ingredients can come together to produce epic snowfall or record cold, the trend in recent years has been for warmer than average temperatures. 

The big difference in the last 20 years has been with overall temperatures.  While six of the last 10 February’s have been warmer than average, there were three consecutive February’s (2013-2015) that were colder than average in the Nation’s Capital.  That was the first such occurrence since 1993-1996, when four consecutive colder than average February’s occurred.  Nine of DC’s 10 coldest February’s on record occurred prior to 1940.  

The Nation’s Capital has had 12 record highs in February, with just one record low temperature in the last 20 years.  Dulles Airport has had a closer ratio in that time, with 12 record February high temperatures compared to seven record low temperatures.  That can partially be attributed to a more significant urban heat island effect within DC compared to where Dulles Airport is located in Sterling, Virginia.  While 14 of the last 20 February’s have been drier than average in the Nation’s Capital, a very wet week is on tap in Washington, D.C.  NOAA’s monthly outlook for February is a 40% chance for wetter than average conditions in the DC Metro Area.

Washington, D.C.’s Warmest February’s by average Temperature (Combining Daily High and Low Temperatures - Source: National Weather Service)

1.  2017: 47.7°
2.  1976: 46.9°
3.  2018: 45.3°
4.  1990: 45.2°
5.  1997: 44.7°
6.  2012: 44.4°
7.  1984, 1949: 43.8°
9.  1981: 43.7°
10.  1954: 43.5°

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Washington, D.C.’s Coldest February’s

1.  1934: 24.6°
2.  1895: 26.2°
3.  1905: 26.4°
4.  1885: 26.9°
5.  1899: 27.4°
6.  1979, 1904: 28.4°
8.  1875: 28.8°
9.  1936: 29.6°
10.  1902, 1901: 29.8°
12.  1914: 30.1°
13.  1907: 30.2°
14.  2015: 30.3°
15.  2007: 30.9°