What makes a Christmas song Christmassy?

Temperature records for Los Angeles in the summer of 1945 are patchy, but 90 in the shade seems to have been the norm. It was during one such scorcher, presumably, that the songwriters Jule Styne and Sammy Cahn pulled up at a red light on the corner of Hollywood and Vine. Cahn suggested going to the beach. Styne had a better idea: ‘Let’s go write a winter song.’ Driving over to the offices of their publisher Edwin H. Morris, Cahn commandeered a typewriter, glanced out the window and typed the exact opposite of what he saw: ‘The weather outside is frightful.’ The Great American Songbook had acquired another Christmas classic.

And ‘Let it Snow!’ is no less classic – and all the more American – for omitting any mention of Christmas. That wasn’t obligatory (Mel Tormé’s ‘The Christmas Song’ was born in the same Californian heatwave). But in a melting-pot America, it made commercial sense.