Perhaps you were buying groceries at the supermarket or flicking through radio channels on the way to work when you first heard it this year - the folksy opening bars of Fairytale of New York, Shakin' Stevens's sleigh bells or the warbling of Mariah Carey.
Whether it fills you with joy or makes you change channels, hearing that first festive song marks the beginning of Christmas for many.
But our desire to stick with the traditional means almost all attempts to write a modern festive hit fall flat.
Looking at the most played Christmas songs of the past five years, the old standards dominate.
Just one song from the past two decades, Leona Lewis's 2013 effort One More Sleep, makes it in to the top 20, according to data from PRS for Music, which licenses music and pays out royalties.
Mariah Carey and East 17, who released their festive tunes back in 1994, come in at number two and number seven respectively.
Other than that, songs from the 1970s and 1980s - and even earlier - still dominate the airwaves.
Paul Clements, executive director of membership, international and licensing at PRS for Music, says: "As the way we celebrate the festive season continues to change and evolve, we can expect more contemporary Christmas songs to reflect that.
"But sometimes, when a season of nostalgia powers the airwaves, you just can't beat a good classic."
Peter Leathem, chief executive of PPL, which licenses the recorded music played in public, says: "Radio seeks to play what its listeners want played, with the most popular being the old classics.
"[They] have longer to rack up airplay familiarity, whereas newer Christmas songs really have to fight for their place on the airwaves."
Our favourite Christmas songs tend to be those that remind us of our childhoods, meaning few become instant classics.
James Masterton, from Chart Watch UK, says: "You consider something like the Mariah Carey song - it was a huge hit back in 1994, but I don't remember it being particularly notable as a cultural touch-point for another 10 years after that.
"It was only in the middle of the last decade that people began to wake up to the fact that, actually, this is a classic.
"Maybe that Leona Lewis song will gain a second wind and become one of the nation's favourites, as the people who've bought it as teenagers grow up and become nostalgic for their bit of their childhood."