My dictionaries of British origin firmly mark this as archaic or dialectal, which will come as a surprise to all the journalists, advertisers and Christmas card scribes who cheerily borrow it as a useful alternative name for the Christmas season. Traditionally, it’s true, it has been more a Northern English and Scots word than a common southern English one, and you will be very unlikely to hear it casually used at the supermarket checkout.
Yule and Yuletide don’t refer only to Christmas day but to all the traditional festive twelve days of Christmas. That goes back to a time before the Christian festival had been thought of. It derives from the Old Norse jól, which was the name of a pagan festival at the winter solstice (and which survives in the modern Scandinavian greeting god jul, Good Yule or Merry Christmas). The beginning of that festival was marked with the ceremonial lighting of the Yule clog or Yule log, a big log laid across the hearth and lit with a piece of wood from the previous year’s log.
A traditional Scots dish was Yule brose, the seasonal version of a kind of porridge made from oats on which was poured the juices from boiled meat. The Edinburgh Magazine reported in 1821 that it was usual to put a ring in the communal bowl of Yule brose; the person who got it in their spoon was taken to be the member of the company to be first married.