Most people like the idea of having a white Christmas. We will get a much better idea for our chances of having snow on the ground on Christmas in a couple of weeks. Until then, we can use historical data to help us determine the likelihood of snow on Christmas.
For most of Wisconsin, the chances are better than about 50%. The challenge of predicting what exactly will happen depends on the weather leading up to Christmas and the conditions on the day itself. December is definitely winter in Wisconsin. For December, the normal average high temperature in Milwaukee is 32.8F with an average low of 20.1F. Those temperature support snow. Of course, we also have wide ranges of temperatures in December. The warmest day on record is 68F on December, 5, 2001. Our coldest day on record was -22F on December 19, 1884. In terms of snow, December gives us an average of 10.6″, once again with a wide range including the record snowfall of 49.5″ in 2001.
Christmas day is also variable with a record low of -12F in 1983 and a record high of 61F in 1982. Snowfall on the ground also covers a wide range. It’s just hard to tell in any particular year what might happen.
The map below shows the historic probability of there being at least 1-inch of snow on the ground in the Lower 48 states on December 25 based on the latest (1981-2010) U.S. Climate Normals from NOAA’s National Climatic Data Center. Dark gray shows places where the probability is less than 10 percent, while white shows probabilities greater than 90 percent.
The 1981–2010 Climate Normals are the latest three-decade averages of several climatological measurements. This dataset contains daily and monthly Normals of temperature, precipitation, snowfall, heating and cooling degree days, frost/freeze dates, and growing degree days calculated from observations at approximately 9,800 stations operated by NOAA’s National Weather Service.
While the map shows the climatological probability that a snow depth of at least one inch will be observed on December 25, the actual conditions this year may vary widely from these probabilities because the weather patterns present will determine the snow on the ground or snowfall on Christmas day. These probabilities are useful as a guide only to show where snow on the ground is more likely. For prediction of your actual weather on Christmas Day, check out your local forecast at Weather.gov.
If you would like to keep track of the snowfall across the United States on a daily basis, see the map below or look for the forecast on our Forecasts page at GreendaleWeather.com. Here, we have forecasts for major cities in Wisconsin.
Regardless of how white your Christmas may be, we wish you a Merry one. To those who celebrate other holidays around this time of year, accept our wishes for good tidings of the season.