How Rare is D.C.’s Arctic Air Outbreak ?

Glen Echo Park, Maryland

As cold as the last week has been for much of the central and eastern United States, temperatures are going to get even colder by the end of this week.  In fact, high temperatures on Friday and Saturday may not reach 20° across the DC Metro Area.  That’s not only brutally cold, but it’s unusual for the Nation’s Capital.  Average high temperatures in Washington, D.C. range from 43° to 44° for the month of January, so Friday and Saturday’s prospective high temperatures are poised to be less than half of average.

The last time a daily high temperature remained below 20° in Washington, D.C. (measured at National Airport) was on January 22, 2014 when it was only 19°.  The last time high temperatures remained below 20° on consecutive days in the Nation’s Capital was on January 19-20, 1994 (8°, 18°).  

Also, January 19, 1994 was the last time high temperatures remained in the single digits and the last time temperatures fell below 0 at National Airport (-4°).  Those two frigid days were part of an exceptionally frigid stretch when high temperatures remained below 20° on four days out of the six-day period from January 15 – 20, 1994.  The last time Washingtonians experienced consecutive high temperatures of 25° or less was February 19-20, 2015 (21°, 22°).

The current wave of arctic air in the Mid-Atlantic Region is approaching rare territory.  For the period from December 28, 2017 through January 7, 2018, temperatures are expected to remain at or below freezing on at least 8 of those 11 days.  That would rival the 10-day-period from January 19 – 28, 2004, when DC’s high remained below freezing on 9 out of 10 days (including 6 consecutive days).  The last time Washington, D.C. had high temperatures at/<32° on five consecutive days was February 11 – 15, 2016.  The last time DC residents had a streak of 10 consecutive days with temperatures at/<32° was in December 1989.  Temperatures have not been above freezing in Washington, D.C. since December 30, but it may sneak above 32° today.

Weather measurements have been made at National Airport since it opened in 1941.  However, prior to that temperature records for the Nation’s Capital were made within city limits and date back to 1871.  Most of DC’s record low temperatures during the winter months occurred prior to 1941 when the entire DC Metro Area was considerably less developed.  Taking temperature readings in such conditions – and away from a body of water like the Potomac River – can make a significant difference.

The coldest winter on record in Washington, D.C. was the 1904-1905 season, which had an average temperature of 29° according to NOAA.  Meteorological winter is comprised of the three month-period of December, January and February.  The coldest winter season since National Airport opened was the 1962-1963 season (31.9°). 

NOAA uses a running 30-year average to measure average temperatures.  Washington, D.C.’s average winter temperature using the most recent (1981 – 2010) data is 38.2°.  A near 50-50 split has occurred over the last 20 years in Washington, D.C., with 12 of the last 20 winters being warmer than average.  However, December 2017 was DC’s first colder than average December since 2010.

Record Low / Record High-Low Temperatures

January 3

Washington, D.C., National Airport (DCA):  -3° (1877) / 10° (1879)
Dulles International Airport, Sterling, VA (IAD): 8° (1979)^ / 23° (1979)
Baltimore, MD (BWI Airport): 0° (1879) / 13° (1879)

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January 4:

DCA: -3° (1877) / 16° (1879)
IAD: 5° (1979) / 20° (1981)
BWI: 4° (1918) / 21° (1981)^

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January 5:

DCA: -3° (1877) / 18° (1896)
IAD: 5° (1970) / 21° (1968)
BWI: 1° (1877) / 18° (1896)

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January 6:

DCA: 2° (1884) / 14° (1884)
IAD: 4° (1999)^ / 20° (1988)
BWI: 5° (1904) / 16° (1912)

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January 7:

DCA: 5° (1884) / 18° (1878)
IAD: 1° (2014) / 18° (2014)
BWI: 3° (2014) / 16° (2014)

^=also occurred in previous years