Will We Have a White Christmas? It's an age-old question that occurs to almost everyone this time of year. The map from the Climate Atlas shows the statistical probability (in percent) that a snow depth of at least 1 inch will be observed on December 25th. Highest probabilities are in northern and mountainous areas of the country. The probability was computed using snow depth observations for December 25th for the full period of record for a given station (rather than just the 1961-1990 climatological normals period).