White Christmas in Washington, D.C.

Longtime Washingtonians know that snow on Christmas Day is a rarity.  That’s despite the fact that December as a whole averages 2.3” of snow.  There are two ways you can have a white Christmas: fresh snowfall on Christmas Day or the remains of a previous snowfall.  The National Weather Service defines a “White Christmas” as having “…at least 1 inch of snow being on the ground on December 25.”  Areas farther north and west of the DC Metro Area have considerably higher odds of seeing a white Christmas. 

The average high and low temperatures in Washington, D.C. on December 25 are 44°/30°.  Since 1884, Washington, D.C. has had measurable snowfall on Christmas Day only nine times or roughly every 15 years.  The last time was on December 25, 2002 and there was 0.2”. 

However, the last time Washingtonians had snow on the ground on Christmas Day was in 2009.  That’s because the Nation’s Capital had its largest December snowfall on record just the week before.  A total of 16.4” was measured at National Airport on December 18-19, 2009.  Although more than half had melted by Christmas, 7” remained on the ground, creating DC’s last official white Christmas.

The coldest Christmas Day in Washington, D.C. occurred in 1983 with high/low temperatures of 14°/3°.  The last time temperatures remained below freezing on Christmas was in 2000 when the high temperature was only 28°.  By comparison, DC’s warmest Christmas on record was in 1964 (72°).  More recently, DC residents had a high temperature of 69° on December 25, 2015 that tied with 1965 for third warmest Christmas.  Such temperatures are more common in late April and early May.

Precipitation of any kind, including rainfall, is much more common on Christmas Day.  DC residents have had measurable precipitation on December 25 a total of 53 times, dating back to 1871.  The most recent rainy Christmas in the Nation’s Capital occurred in 2015.

Washington, D.C.’s snowiest Christmas Day’s  (Source: NOAA)

1.  5.4”  (1962)
2.  4.5”  (1909)
3.  4.3”  (1969)
4.  1.0”  (1902)
5.  0.6”  (1935)

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“White” Christmas’ in D.C. during the last 30 years

1.  2009
2.  2002
3.  1993
4.  1989

Which Do You Prefer: A Wet 2018 or a Warm 2019 ?

Although 2019 will finish as a wetter than average year in the Nation’s Capital, it can’t compare to last year, which was DC’s wettest year on record.  There are some interesting comparisons between DC’s predominant weather patterns in 2018 vs. 2019. 

Through December 10, DC has had 40.46” of rain, creating a year-to-date rainfall surplus of 2.69”.  By comparison, there was an annual rainfall surplus of an astounding 23.01” through the same period last year.  Although 2018 got off to a drier than average start through March 31, the final nine months of the year were exceptionally wet.  It’s hard to imagine given how wet last year finished, but Washingtonians actually had an annual rainfall deficit of 1.26” on April 1, 2018, because January and March of last year were drier than average.  

Meanwhile, six of the first seven months of 2019 were wetter than average.  What changed was that the period from August – November saw three drier than average months.  For example, September 2019 was one of the driest in recent memory with only 0.25” of rain.  But Washingtonians experienced the wettest October in more than a decade with 6.66” of rain.  July 2018 and July 2019 each have something in common.  Both months had a day with an exceptional amount of rainfall.  A daily record of 4” occurred in the Nation’s Capital on July 21, 2018, while 3.44” fell on July 8, 2019.  Getting daily rainfall totals of 3” or more is exceptionally rare in the Mid-Atlantic Region absent a tropical system.

This year will finish as much warmer than last year.  Seven out of the 12 months of 2018 were cooler than average and nine were also wetter than average.  By comparison, last month was the first cooler than average month of 2019 in Washington, D.C.  In July 2019, DC residents endured the longest heat wave in nearly three years.  

November and December 2018 were each warmer and wetter than average in the Nation’s Capital.  This trend continued in January and February 2019.  There was a weak episode of El Nino last winter, so having a wetter than average winter was not unusual.  By comparison, there is currently no El Nino or La Nina present, meaning “ENSO neutral” conditions currently exist according to NOAA’s December update.  NOAA’s Outlook for the rest of the winter season is for warmer and wetter than average conditions in the Mid-Atlantic Region.

Weather Quiz

True or False.

Accumulating snowfall has occurred in the Nation’s Capital in more than 75% of December’s over the last two decades.