It’s that time again, when children and adults alike dream for an iconic White Christmas. When it comes to history, we’re certainly fighting an uphill battle across the Washington, D.C. region. The I-95 corridor more or less marks the 10% chance area, with odds increasing to about 25% of the time for our far northwest suburbs.
Not until you get well into elevation, well to the north and west, does a White Christmas become more of a regular occurrence.
What constitutes a White Christmas? By the standard definition, it is having 1” or more of snow on the ground at 12z (7 a.m. locally) the morning of Christmas. Yes, this can mean a snowstorm that starts after 7 a.m. doesn’t “officially” make it.
In Washington, D.C. itself, there have been 13 official White Christmas’s that started the day with snow cover greater than 1” since the late 1800s. This is a long-term simple average of 10.5% through 2011.
The 7” of snow on the ground (remnants of Snowpocalypse) in 2009 ties for the high on that account, though the day was not a good one for snow lovers. The day started chilled, but temperatures warmed as a rain event arrived and washed the snow away heading through the night.
The 1960s were particularly kind for those wanting snow on the ground while opening presents, with 5 instances of a White Christmas. Another plentiful period occurred from 1908 through 1914.
When it comes to historical odds of snow falling in D.C. on or around Christmas, CWG’s Winter Weather Expert Wes Junker summarized them last year as the following:
-About a 46% chance of getting a dusting Christmas week
-About a 20% chance of getting 1” or more Christmas week
-About a 3% chance getting 1” of snow on Christmas, and
-A 1 in 50 shot of 4” or more on Christmas
We’ve had 10 instances of measurable snow falling in D.C. on Christmas itself. This comes to a long-term average of roughly 8% through 2011. The highest of the daily totals occurred in 1962, when 5.4” fell. In two other instances, 1909 and 1969, storms dropped over 4” in the city on the 25th. The rest of the Christmas accumulating snowfall days were meager (1 inch or less), and sometimes mixed with rain.
18 Christmas’s featured non-accumulating snow, or a trace (at least some snow in the air).
Since Christmas Eve snow can help set the mood and also prompt a White Christmas, it’s worth at least noting that both 1912 and 1966 saw significant Christmas Eve snows of 6.5” each.
As recently as 2002, both Christmas Eve and Christmas Day saw accumulating snow. However, in the city, that storm is mostly remembered as a cold rainy one, particularly on Christmas itself.
Of course, we don’t assume that the data here is wholly representative of the entire area, and in general would point back to the U.S. climatological map when it comes to other spots.
As noted above, the further north and west you are -- particularly with elevation -- the better your odds, particularly on the snow cover stats. Similarly, those chances drop to the southeast.
However, it’s not hard to imagine a year like this one where the whole area really faces a similar same chance (at least until potential storminess ahead comes into focus). Big snows before and near Christmas can happen, but they aren’t necessarily an expectation so early in the winter season.
How does D.C.’s White Christmas history differ from your perceptions, if at all?