I was trying to quit (ish) last xmas and I didn't get anywhere. Not because of the time of year rather that I hadn't quite finished drinking. Same happened a few years earlier when I was seeing an addictions counsellor who was trying to help me cut down my drinking. I think I used the excuse that it was Xmas as the reason I couldn't but really I just didn't want to stop drinking or even cut down (I was forcibly referred at that time).
I think when you have made the decision to stop drinking and never drink again then it doesn't matter what time of year it is. Of course it is harder being around other drinkers and that's more likely to happen around this time of year. Even after 9 months I can't wait til Xmas is over so I don't have any forced parties to go to. But I am not worried that I will drink. And I don't owe anyone an explanation. It isn't compulsory to drink at Xmas (though a year or so ago I may have argued with myself about that one
).
I think the thing to remember is that if everyone else is drinking then they're not going to notice you aren't because they're drunk. As long as you don't interfere with their drinking they won't care.