Peoria, Ill. (WMBD) – We’re now halfway through the month of December, which has been quite warm and has brought Central Illinois no measurable snow. Whether you love it or hate, many people will acknowledge that it might be nice to have a little snow on the ground for Christmas morning. So that begs the question, what are our chances of seeing a white Christmas in Central Illinois?
What is the definition of a white Christmas?
I’m sure everyone has a different idea as to what constitutes a white Christmas, but according to the National Weather Service, a Christmas is considered white if there’s at least one inch of snow on the ground. It doesn’t matter if snow is falling or not.
What is the historical probability of a white Christmas?
Based on the new U.S. Climate Normals, which are comprised of data between 1991 and 2020, the historical probability of having at least one inch of snow on the ground ranges from 25-40%. Peoria’s historical probability sits at 31% while Bloomington/Normal has a 29% chance. In other words, Peoria and Bloomington experience a white Christmas in 3 out of every 10 Christmases. As one might expect, the chances are higher further north with locations along I-80 carrying a 35-40% chance. The last time Peoria had a white Christmas was in 2017 when there was 3 inches of snow on the ground.
You can see what your local historical probability of a white Christmas is by checking out this interactive map from NOAA.
What are our chances this year?
While the month has been unseasonably warm and relatively snow free, there are some signs that the pattern will be trending cooler for the final week of December and into the New Year. This would be, in part, the result of negative phases of the Arctic Oscillation and Eastern Pacific Oscillation which help drive colder temperatures southward and into the eastern U.S. The signal doesn’t necessarily scream frigid temperatures, but it does suggest that we could be in for a more seasonal weather pattern and perhaps better opportunities for snowfall.
The latest ensemble model guidance suggest that there could be some opportunity for snowfall the week of Christmas with the best chances coming around December 20th – 21st. However, while there may be some snow, the signal for anything meaningful looks quite low. As of December 13th, the European model ensembles (EPS) gives Peoria a 14% chance of receiving an inch of snow or more through Christmas day. Even if we were to see an inch of snow, there’s an even lower probability that much is actually on the ground when Christmas arrives.