Winter carries its own weight in a story, the days going short, the cold closing everyone in, everything feeling like it's building toward something. That's true whether Santa shows up or not. A boy questioning what he believes rides a train to the North Pole. Four evacuated siblings step through a wardrobe into a kingdom trapped under permanent snow, with the real history of WWII sitting right behind the fantasy. A girl spends her whole childhood hiding what she's capable of, until her fear becomes an actual blizzard that swallows a city. Even the quiet ones carry it: a boy and a snowman spend one night together with no dialogue at all, and everything that happens between them has to be read rather than heard.
Three of these, The Polar Express, The Lion, the Witch and the Wardrobe, and A Christmas Carol, are close enough to their source books to hand a class both and ask what changed and why. Elf gives students an unusually easy character to read, since Buddy never hides what he thinks or feels. Klaus and Rise of the Guardians build their own mythology from scratch instead of retelling a familiar one, and The Star does the opposite, retelling a very familiar story from an angle nobody usually bothers with, the animals standing off to the side. Pick based on the grade you're teaching and the time you've got, not just what's on the calendar.