While those of us in the northern hemisphere are told that today is the “first” day of winter, it’s actually considered MID-winter by many. Also called Jol, Yule, etc. Santa Claus is a modern interpretation of the ancient Holly King, the God of the Waning Year. He is vanquished by the Oak King, the God of the Waxing Year.
Santa’s sleigh is the solar chariot, the eight reindeer are the eight Sabbats – their horns representing the Horned God– the North Pole symbolizes the Land of Shadows and the dying solar year, and the gifts are meant both to welcome the Oak King as the sun reborn and as a reminder of the gift of the Holly King, who must depart for the Oak King to rule.