I'm atheist and i celebrate a combination of midwinter and new year i call it 'christmas' simply because it is when we get off work and it's the norm in our society but i wouldn't care too hoots if instead of being off work on 25th and 26th december and 1st and 2nd january we were all off on midwinters day instead or had all four days at hogmanay.
"The roots of Hogmanay perhaps reach back to the celebration of the winter solstice among the Norse, as well as incorporating customs from the Gaelic New Year's celebration of Samhain. In Europe, winter solstice evolved into the ancient celebration of Saturnalia, a great Roman winter festival, where people celebrated completely free of restraint and inhibition. The Vikings celebrated Yule, which later contributed to the Twelve Days of Christmas, or the "Daft Days" as they were sometimes called in Scotland. The winter festival went underground with the Protestant Reformation and ensuing years, but re-emerged near the end of the 17th century."