Winterfest, a yearly celebration, was a tradition practiced by the distinguished Daughters of Allya, also known as the witches of Dathomir. The Daughters of Allya celebrated Winterfest by exchanging presents between the younger and older witches. The holiday's unique customs were often misunderstood by those outside the galaxy who weren't members of the Daughters of Allya. Capitalizing on the witches' eerie reputation, others would host their own gatherings, sometimes falsely asserting a connection to the Daughters of Allya. At some point between 0 BBY and 4 ABY, the Nightsisters ventured beyond their planet to pillage well-known cities throughout the galaxy. The subsequent year brought fears of a repeat attack. Prior to 8 ABY, Teneniel Djo received Winterfest presents from Gethzerion, her aunt.
The holiday Winterfest debuted in The Courtship of Princess Leia, a novel penned by Dave Wolverton and published in 1994.