Written/Compiled by the National Weather Service in Des Moines

What are the Chances of a White Christmas?

At this time of year many often wonder how likely it is that we will have a White Christmas. The answer to this question varies depending on location and how one defines a White Christmas. The most widely accepted definition in the meteorological community is at least one inch of snow on the ground on Christmas morning; however some people consider a deeper snow pack necessary, or define a White Christmas as snow actually falling on the holiday. Following are the odds of a White Christmas in any given year, compiled from historical weather records, for various definitions at both Des Moines and Waterloo. This should not be interpreted as a forecast specifically for Christmas of 2012, as these are percentages derived only from the historical records.

Des Moines

Climate records at Des Moines date back to August of 1878, but snowfall records did not begin until December of 1884. That yields 128 Christmases (1884-2011) of snowfall data from which the following percentages were computed:

Percentage of Christmases with –
At least 1” of snow on the ground on Christmas morning: 41%
At least 2” of snow on the ground on Christmas morning: 28%
Any snow falling on either Christmas Eve or Christmas Day: 62%
Measurable snow (at least 0.1”) falling on either Christmas Eve or Christmas Day: 34%

Waterloo

Climate records at Waterloo date back to February of 1895. That yields 117 Christmases (1895-2011) of snowfall data from which the following percentages were computed:

Percentage of Christmases with –
At least 1” of snow on the ground on Christmas morning: 58%
At least 2” of snow on the ground on Christmas morning: 40%
Any snow falling on either Christmas Eve or Christmas Day: 48%
Measurable snow (at least 0.1”) falling on either Christmas Eve or Christmas Day: 29%