D.C.’s Warm and Dry Start to 2023

 

The Washington Monument as seen from the National Mall

January 2023 will finish as the third warmest on record in the Nation’s Capital and warmest since 1950.  Only January 14 was colder than average, just barely.  It has also been a drier than average month in Washington, D.C.  Warmer and drier than average weather is not a good combination for winter weather enthusiasts. 

No measureable snowfall has occurred so far this winter in the Nation’s Capital.  While no measurable snowfall through the end of January is unusual, it isn’t record setting.  The latest first accumulating snowfall in the Nation’s Capital was on February 23, 1973 (0.1”), according to the National Weather Service. 

What stands out about this month is the almost daily warmer than average weather.  Although only one day of record warmth occurred in the Nation’s Capital (69° on January 3), all but seven days have remained above freezing.  January is normally the coldest month of the year, so it’s remarkable to remain above freezing for so much of it.  D.C.’s coldest temperature this month was 29° on January 15 and 16.  That’s helped produce an average monthly temperature (combining daily high/low temperatures) of 45.3°.

In addition to warmer than average temperatures, it has also been a dry month with only 1.48” as of January 30.  This is appreciably below D.C.’s monthly average of 2.86”.  January 2023 will finish as D.C.’s second driest January in the last decade.  It is the fifth drier than average month over the last six months. 

Dulles Airport in nearby Sterling, Virginia has also been warm.  January 2023 will finish as the warmest on record with an average monthly temperature of 42.4°.  Dulles Airport has also had below average rainfall with only 1.29” of rain as of January 30.

Although February will get off to a cooler than average start, NOAA expects February 2023 to be a warmer than average month in the Nation’s Capital.  However, the right ingredients need to come together only once to produce accumulating snowfall. The last time there was accumulating snowfall in Washington, D.C. was on March 12, 2022 (0.9”).

Warmest January’s in the Nation’s Capital (Source: NOAA)

1.  48° (1950)
2.  46.8° (1932)
3.  43.8° (1937, 1890)
5.  43.6° (1990, 1913)
7.  43.1° (2006)
8.  43.0° (1998)
9.  42.9° (1974)
10.  42.6° (1949, 1933)

Warmest January’s at Dulles Airport (Source: NOAA)

1.  41.8° (2006)
2.  40.8° (1990)
3.  40.1° (1998)
4.  39.4° (2017)
5.  39.1° (2007, 2002)
7.  38.9° (2020)
8.  37.8° (2012, 1974)
10.  37.4° (2013)

Rainfall Trends in the Nation’s Capital

 

A view of Alexandria in the distance from National Harbor, Maryland

January 2023 is well-positioned to finish as D.C.’s fifth drier than average month in the last six, with the exception of December 2022.  Since last August, Washington, D.C. has accrued a rainfall deficit of 4.14” through January 26. 

December 2022 finished with a rainfall surplus of 0.45” in Washington, D.C.  That was largely the result of two exceptionally rainy days that each saw over one inch of rain (December 15, December 22).  Without the combined rainfall total of 3.04” on those two days, last month would have finished with only 0.82” of rain (roughly 25% of D.C.’s December average of 3.42”).  That helps illustrate that with the exception of those two rainy December days, the last six months have been very dry in the Nation’s Capital overall.

Our current drier than average period bears a lot of similarities to another similarly dry period that occurred in late-2017 and early-2018.  Back then, the Nation’s Capital also had five drier than average months in the six-month period of August 2017 – January 2018.  The rainfall deficit in that time swelled to 8.55”, more than double the current rainfall deficit in the Nation’s Capital.  That underscores just how dry those six months were in Washington, D.C.  The only wetter than average month during those six months occurred in August 2017 with a rainfall surplus of 1.33”.

The six-month period in late-2017 and early-2018 was part of a larger 32-month period (August 2015 – March 2018) when all but seven months were drier than average in the Nation’s Capital.  The combined rainfall deficit for that stretch was 16.42”.  As longtime Washingtonians may recall, 2018 went on to become D.C.’s rainiest year on record (66.28”), according to NOAA.  Going from an extended, years-long drier than average period to setting a record for rainiest year represents a major shift in the weather pattern. 

More modest changes are on tap when looking at NOAA’s 8 – 14 day precipitation outlook that covers almost the entire first half of February.  It calls for potentially above average precipitation in the D.C. Metro Area.  February is D.C.’s snowiest month of the year on average.  Washingtonians could see the first accumulating snowfall of the 2022-2023 winter season over the next couple of weeks. 

Weather Quiz

 

How many of Washington, D.C.’s Top 10 largest snow events occurred in January ?

A.  3

B.  5

C.  6

D.  8