Dreaming of... eh, Mapping a white Christmas

Jesus Christ and Bing Crosby have more in common than a rapidly aging fan base. They share the responsibility for an annually recurring socio-meteorological phenomenon — White Christmas Anticipation (WCA).

Jesus is to blame for having his fake (1) birthday in mid-winter, Crosby for famously singing about his fond recollections of the snowy Christmases of yesteryear (2). With over 100 million copies sold worldwide, "White Christmas" is the best-selling single of all time.

Of course, WCA only occurs in regions where there is a degree of uncertainty that a White Christmas will actually happen. So no WCA in Phoenix, Arizona (probability 0 percent), nor in Fairbanks, Alaska (probability 100 percent).

Any place in between, and you can bet the talk on the news and in the shops in the run-up to December 25th will at some point turn to the likelihood of snowfall (3). As past occurrences have been archived, that likelihood can be mapped, as it is here.