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’m near that start. Once Santa is introduced in the Macy’s parade, it’s open season.
Alternatively, the end of the MST3K Turkey Day Marathon also counts as the start of the Christmas season.