My mom and I were lucky enough to spend Christmas week in Yellowstone. It was the best. We rode all over the park in old 70s Bombardiers that would make Wes Anderson jealous. We went of a night tour of Fountain Paint Pots under the stars. We saw five wolves, a coyote, two otters playing together in an ice cold river (there was literally ice floating past them), and more elk and bison than we could count.
If you ever have the chance, get to Yellowstone in winter! It blows summer Yellowstone away, and that’s no small feat.