Thanksgiving and Christmas are then some of the quietest times in terms of outages. Of course, the interval right after then is usually worse, since all of the backlogged changes from the holidays land at once.
There is a period just before the freeze which can also get a bit hectic, but we should be well beyond that point for most relevant services by now. Don't know the exact dates since I left in September. But your point stands: holiday freezes exist and are taken seriously.
“Diff”, not PR.