This article is from the archive of our partner National Journal

If you're dreaming of a white Christmas, you may be in luck.

According to a NOAA analysis, the U.S. has seen an overall uptick in the number of snowy days during the week of Christmas in the past two decades, compared with the previous two decades.

But all of that snow has not fallen evenly. The map below shows parts of the United States that have seen more snow-filled days marked in blue, while places where the number of snowy days has declined are shaded brown. The darker the color, the more stark the change.

To create the map, scientists at the Rutgers University Snow Lab calculated the change in the number of snow-covered days across the U.S. from 1990 to 2013 compared with 1966 to 1989.

Which states have gotten more snow at Christmas? New Hampshire and the southern half of Maine, along with central Iowa, western Virginia and North Carolina have all seen up to a 25 percent increase in the number of snowy days during the holiday week.

In contrast, much of Nebraska and parts of Montana and Oregon have seen as much as a 25 percent decrease in snow-covered days.

The analysis comes with at least one major caveat: Crunching the numbers on snowfall for a single week does not provide enough data to determine meaningful trends.

Rutgers researchers also note that while the map shows an overall increase in snowfall, Northern Hemisphere snow cover has actually decreased substantially in spring and early summer across the U.S. in recent years.

This article is from the archive of our partner National Journal.

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