Christmas Idioms  聖誕節慣用語

white Christmas
白色聖誕

Explanation :
This idiom probably derives from a song made popular by Bing Crosby.  Christmas is 'white' in many parts of the United States because it is winter at that time of year and there is often snowfall before Christmas day.  So when you hear reference to a 'white Christmas' it has to do with a snowy Christmas.