The year's end festival takes place over the spare four days (one shift-round) that aligns the calendar with the solar year at the end of Late Fallow. This shift-round doesn't fall within a shift-cycle.
In the Islands, one traditionally decorates with strings of colourful wooden beads.
Universally, it's a time of feasting.
Most of the traditions, even the Asterist ones, are ultimately Earthist in origin.
One typically asks of friends at Festival, "what's happened this year that you'll remember? And what does the coming year hold?"