DC’s December Record Snow and Warmth

Broomes Island, Maryland (Courtesy: Kayce Kerr)

The storm that brought significant snow and rain to much of the southern United States has been tantalizingly close to bringing the Nation’s Capital appreciable snowfall today.  So close that DC's southern suburbs have had small accumulations while nearby southern Virginia has had double-digit snow totals.  It’s worth pointing out that Washingtonians have had both record snow and record warmth during the month of December over the last 20 years.  However, such conditions often have had little bearing on the rest of the winter barring, the presence of El Nino or La Nina or phase of the North Atlantic Oscillation (NAO).

The Nation’s Capital averages 2.3” of snow in this month and measurable December snowfall has occurred in 16 of the last 24 years – including last year.  December 2009 was the snowiest on record in Washington, D.C. (16.6”).  Longtime Washingtonians may remember the record December 18-19 snow that year which remains one of DC’s 10 largest snowstorms.

DC residents also experienced the warmest December on record just three years ago.  December 2015 finished with a total of 14 days with high temperatures in the 60s and 70s, while low temperatures only fell at or below freezing twice with no snow.  Washingtonians also experienced the warmest four-day stretch on record on December 4 – December 8, 1998, when high temperatures ranged between 73° and 79° (setting records on three of the four days).  Not surprisingly, four of DC’s warmest Decembers have occurred since 2001.  That’s compared to nine of DC’s ten snowiest Decembers that occurred in 1966 or earlier.

Having a warm start to winter doesn’t necessarily mean the rest of the winter will be warmer than average with below average snowfall.  Area residents may recall that following DC’s warmest December in 2015, DC’s fourth largest snow storm occurred in January 2016.  At the opposite end of the spectrum was December 1989, which finished 11.8° colder than average with nearly four times the average monthly amount of snowfall (9”).  In addition, 1989 remains DC’s only year that had snow on the ground on both Thanksgiving and Christmas.  Meanwhile the rest of the 1989-1990 winter was warmer than average with below average snowfall.  

Having one storm give the DC Metro Area a glancing blow should not be discouraging to area winter weather enthusiasts.  That’s because the right elements have to come together only once to bring Washingtonians a classic winter storm capable of producing the seasonal average of snow in just one event (15.4”).  For example, a sufficiently cold air mass combined with the appropriate storm track close to the East Coast could bring the requisite moisture into the DC Metro resulting in a winter wonderland.