White Christmas not likely in areas

The unforgettable lyric to Irving Berlin’s classic holiday song may need a rewrite: “I’m dreaming of a warm Christmas, unlike the ones I used to know” . . .

Exceptionally mild weather dominating the Lower 48 this month shows little sign of meaningful change through the Christmas holiday. This means rather underwhelming chances for a white Christmas in many parts of the United States, a state of affairs to which we probably should become accustomed.

Our warming climate appears to be eating away at white Christmas chances, newly available data shows.

This week, the National Oceanic and Atmospheric Administration released white Christmas probabilities across the United States, basing them on the most recent 30 years of climate data that revealed broad decreases compared to just a decade ago. The changes “are consistent with the reality of longterm warming,” NOAA wrote.

The observed changes have been rather subtle, but “more areas experienced decreases in their chances of a white Christmas than increases,” the agency said. NOAA’S criterion for a white Christmas is one inch of snow on the ground on the morning of Dec. 25.

How have white Christmas chances changed in our nation’s cities in the past decade? We analyzed NOAA’S white Christmas data in the 25 biggest cities, from Seattle to D.C., and, unsurprisingly, found declines in most of them:

• 18 of the 25 cities saw their chance of a white Christmas decrease; Denver and Columbus saw the largest drops (six percentage points). Washington D.C.’S odds of a white Christmas plummeted from around 8% to just a little over 4%.

• Four cities’ chances were unchanged (Minneapolis, Indianapolis, Portland and Dallas)

• Three saw their chances increase, but only by one or two percentage points (New York, Philadelphia and Raleigh)

Our results are consistent with an analysis from CNN, which found 64% of the 2,000 locations in NOAA’S database exhibited decreases in their white Christmas chances.