Once upon a time it used to snow in December in Washington. Nowadays, it’s much more scarce.
In recent years, the area has been particularly shortchanged.
The District has only topped its December snowfall average of 1.7 inches twice since 2009. This year — almost midway through the month — we’ve received just the paltry 0.1 inches that fell Monday morning, although more coated areas north and west of downtown.
Since 2009, snowfall has been below average in December 11 times. In 10 of those 11 instances, less than half an inch fell.
The lack of December snowfall over the last 10 to 15 years fits into a long-term downward trend, only slightly offset by the “Snowpocalypse” storm in December 2009 that unloaded 16.4 inches. If we were to take that away, our recent snowfall average would be even less. For example, it would shave 1.5 inches off the average snowfall of the decade from 2000 to 2009.
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If we examine 30-year averages for the District’s December snowfall in Washington weather records that date to the late 1800s, the maximum was 4.2 inches in 1973. Now, we’re at the minimum of around 1.5 inches.
That maximum in 1973 came on the heels of the snowy 1960s, when flakes fell regularly and in abundance. Six Decembers that decade had 6 inches or more, and only one featured no accumulation. The 62.4 inches that fell in the 1960s in December easily tops the 46.5 inches in the 1910s — the next snowiest December decade.
Even in the snowier decades of the past, there was considerable variability in December snowfall. That remains the case. But the long-term trend is unmistakable.
Much of the decline in December snowfall can be attributed to rising temperatures — a consequence of urbanization and human-caused climate change. The average December temperature has risen more than 6 degrees since 1900 and about 3.5 degrees since 1950.
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The average December temperature — based on data from 1991 to 2020 — has climbed to 41.7 degrees. Average low temperatures have risen from the upper 20s to above freezing.
For temperatures to be cold enough to snow, they now must be considerably colder than the norm compared with the past. The snowy December of 2009, for instance, was about 4 degrees colder than normal.
The past decade has featured the warmest (2015) and second warmest (2021) Decembers on record. December 2015 was 9.5 degrees above the norm.
Because of the rise in temperatures, more of December’s storminess is bringing precipitation as rain rather than snow.
This December is resembling so many others in recent years: Warmer-than-normal conditions are expected for most of the back half of the month. An active storm track may still allow for the occasional (probably minor) snow threat. Most precipitation will probably fall as rain for the rest of 2023.
In January and February, the pattern may change to a more wintry one, which would increase snow potential. While the D.C. area has seen a long-term decline in December snowfall, those months — which are colder — have not experienced the same decrease.
Jason Samenow contributed to this report.
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