Along with that snowflake of truth, the National Weather Service posted a graphic, "White Christmas History for Philadelphia, PA," with 70 trees.

Christmas is approaching nearly as fast as Santa’s sleigh, but almost anyone in the United States fantasizing about a movie-worthy white Christmas might need to keep dreaming. Early forecasts ...

For the Met Office to declare a white Christmas, a single snowflake must be observed falling in the 24 hours of Christmas Day.

Bookmakers, meanwhile, tend to have a slightly different definition. William Hill , for example, defines a white Christmas as snowflakes falling at one of the UK’s 12 major airports.

The Met Office used to record a white Christmas if a snowflake fell on their headquarters in London.

The Met Office defines a white Christmas as when one snowflake is observed to fall in the 24 hours of Christmas somewhere in the UK.