I've seen discussions about when it is that the Christmas season officially starts and ends, and for the Scalzi household, it starts after dessert on Thanksgiving, and ends on Epiphany (which is Jan 6), although as a practical matter it ends whenever Krissy decides it's time to put away decorations, so, usually that means Jan 2nd or so.
@scalzi I am the Source of Christmas Joy in the family. No one else does much of anything, so it all falls to me. I have to start shopping as soon as possible, because selection tends to be bleak and crowds horrific from this weekend on. I also start in on the baking and cards early so I can actually enjoy December instead of doing the anxiety zoomies. Decorations don't go usually go up until after our annual T-day road trip, though.