When does Father Winter leave?

I had Winterfest a couple days ago. For me he left after an hour or two when my sims went to bed after completing the 'ask for gift' tradition from him. I didn't see him leave but when they woke up the next morning he was off the lot. So I find it strange that he's stuck around in other people's games.

Although now every once in awhile he calls me up to invite me to places and parties =\ Which is a bit strange.