If you’re been blaring “I’m dreaming of a white Christmas…” this holiday season, odds are, you’re not alone. But the odds of actually seeing a white Christmas are historically slim.
Before we examine the chances of a white Christmas, one must first understand the threshold to meet such a holly jolly wintry requirement.
WHAT DEFINES A WHITE CHRISTMAS?
❄️1” or more of snow on the ground Christmas Morning (we’ll use this one. It’s the most widely accepted definition)
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❄️Any new snow on December 25
Now that the flurry of formalities is out of the way, let’s look at our odds of a white Christmas in New England?
This map looks at weather stations across the United States on December 25 (between 1991-2020) based on the latest Climate Normals from NOAAs National Centers for Environmental Information (NCEI).
Darker colors represent lower chances of a white Christmas. Most, if not all, of New England is caught in the crosshairs of some form of flakes on Christmas Day. The South Coast has the lowest odds, generally less than a 15% chance. But in a matter of miles inland, the chances increase. Historically, Woonsocket, Rhode Island has a 36% probability, Walpole, Mass. has a 41% odds of being transported into a winter wonderland, and Salem, Mass. has a 27% chance. For Boston, the probability sits roughly higher than 30%.
The odds are considerably higher for those in elevation and latitude. Concord, New Hampshire has a 63% probability of at least 1 inch of snow on the ground on Christmas Day.
Snow on Christmas Day sounds fun...but if you caught the caveat in the widely accepted definition of a white Christmas, you’ve probably connected the dots by snow and realized, that inch of snow, could be old snow on the ground. That old snow gets pretty crummy on our cars and sidewalks.
So, let’s dig a little deeper (into the snow)…and see what the chances of a true winter wonderland are for New England. Snow on Christmas Day itself.
Compiling 130 years of data, there have been 45 Christmases (or 34%) with a trace of snow (or more) on Christmas Day. A trace is defined as accumulating snow that never reaches 0.1.” This lets us know that roughly 34% of Christmases, in more than a century, have had snow falling on the day itself.
Of those 45 years, 8 Christmases (6.15%) recorded at least an inch of snow recorded on December 25.
CLIMATE OF THE 12 DAYS OF CHRISTMAS
While the odds of a white Christmas are low, the chances of a warming 12 Days of Christmas (December 25-January 5) are much higher.
In a warmer climate, it’s likely more wintry precipitation will fall as rain, rather than snow across the country. Since 1969, 97% of 246 recording locations evaluated in the US have been warming.
Temperatures have climbed from coast to coast. One location that’s warmed the most is Burlington, Vermont (by 9.1°F).
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This goes beyond snow falling (or not) on Christmas Day. A warming planet eventually can have an economical impact too. Threatening winter sports and recreation like skiing, skating, ice fishing and snowboarding, leaving them all at risk by a rising number of above-freezing days.
WILL THERE BE A WHITE CHRISTMAS IN BOSTON THIS YEAR?
It’s a bit too early to say with exact certainty whether or not we’ll have a White Christmas in Boston. History tells us it’s not impossible, but it also isn’t likely.
For a little more clarity one tool we can use is climate data from the NOAA.
The days leading up to Christmas Day itself will likely have below-normal temperatures for much of the country, New England included. The core of the cold will be across the Midwest & Great Lakes.
This upper air pattern at 500 mb shows us where the anomalously cold air will be. All things remaining equal, it, at the very least, sets us up for a cold Christmas week.
Image courtesy of: WeatherBell
