Original: Some of the least likely white Christmases that have happened include the 2004 Christmas Eve Snowstorm, which brought the first white Christmas in 50 years to New Orleans and caused the first recorded white Christmas in Houston, Texas.
Simplified: For example, in the United Kingdom, there are not a lot of White Christmases; but in Canada, there is almost always a White Christmas. Ireland's last "official" White Christmas was in 2004.