Will a cold January follow a mild December ?

 

A winter's day in the nation's capital

The nation’s capital finished 2023 with a warm and wet December. It tied as DC's fifth warmest and fourth wettest on record. Despite last month's warmth, there was accumulating snowfall in December for the first time since 2019 with 0.1" at National Airport on December 11. Three December days also had an inch or more of rain, helping alleviate the drought conditions that have persisted across much of the DMV during 2023.

January is the coldest month of the year in the nation’s capital with an average monthly temperature (combining daily high/low temperatures) of 37.5°. That’s an increase over the previous average of 35.7°.  NOAA recently updated its temperature and precipitation averages to reflect the 30-year period of 1991-2020. Since the 2010s were a much warmer decade than the 1980s, it’s not surprising that January’s average temperature increased by 1.8° when the 2010s replaced the 1980s that were used in NOAA’s previous data set (1981-2010).

DC’s coldest time of the year based on average temperature occurs in mid-January. The daily average high/low temperatures in the nation’s capital are 44°/30° for a six-day stretch from January 14 – January 19. The warmest January temperature on record was 79° on January 26, 1950. By comparison, DC’s coldest January temperature was -14° on January 1, 1881. Although six of the last 10 January’s have been colder than average, January 2023 finished as DC's third warmest on record. 

Although the nation's capital averages 2.86" of January rainfall, Washingtonians have experienced below average precipitation in seven of the last 10 January’s. That includes DC’s fourth driest January on record in 2018 (0.94”). DC's January snowfall average fell from 5.6” to 4.9” for NOAA's 30-year period of 1991-2020. January 2023 was DC's first since 2006 without any measurable snowfall.

It’s important to remember January doesn’t have to be colder than average to be snowier than average. January 2005, for example, was a snowier than average month in the nation’s capital with 6.4” of snow, but also finished 0.1° warmer than average. DC's last snowier than average month was January 2022. However, the nation’s capital hasn’t had consecutive snowier than average January’s since 2009-2010.

NOAA expects this month to be warmer and wetter than average. However, the right ingredients need to come together only once to produce an epic winter storm like what happened in January 2016, which was D.C.’s fourth largest snow event on record.