it's on!

Unless Santa isn’t tracking a Gregorian calendar. He could be on a Julian or other historical calendar- but most likely, much in the same way that there is a “Fiscal year” in business- he would use a “year” as a relevant period between either one Christmas and the next, or between the cut off date when the elves begin construction of toys to the next cut off. So it would be unlikely that Santa would simply ignore the last 6 days of the Gregorian calendar year.