By Climate Central
It’s that time of year when people are wondering about their chance for a white Christmas. Despite historic, early-season snow from Calgary, Alberta to Roanoke, Virginia, the overall snow-covered area in North America is shrinking as temperatures rise with climate change.
Christmas extremes & warming trends across the U.S. and Puerto Rico
The U.S. December temperature average has climbed just over 2°F in the last half-century. Over two thirds of the 244 cities analyzed have warmed at least 1°F since 1970, while only 3 percent have cooled 1°F. And several northern cities have warmed more than 6°F, including Burlington, Vermont; Fargo, North Dakota; and Presque Isle, Maine. This warmer weather can lead to more winter precipitation falling as rain, as shown in a Climate Central report.
But even with rising temperatures, we still get snow and rounds of extreme cold. In fact, the snowiest Christmas on record dumped an incredible 21 inches in Erie, Pennsylvania last year. And as our snow & ice toolkit explains, a warmer atmosphere will increase the moisture that leads to precipitation. So even though temperatures are stacking the deck against a white Christmas, there’s still a chance of drawing some wintry weather where temperatures are cold enough.
Methodology: Christmas temperature extremes and December temperature trends are calculated using data from the Applied Climate Information System. Extremes are given for each station’s entire period of record, while trends begin in 1970 for consistency between stations. Displayed trend lines are based on a mathematical linear regression.
A White Christmas is defined as having at least 1” of snow depth, based on analysis of the 1981-2010 NOAA/NCEI climatological normal. Click here for more details.
This originally appeared on Climate Central.