Winter is our favorite time of year to visit Yellowstone and Grand Tetons National Parks. Now don't get us wrong, we love those parks in the summer, too. The winter is just that much more scenic and all the wildlife come off the high mountains to feed in the valleys. Elk, bison, coyotes, moose, wolves, bald eagles, and more are almost guaranteed sightings. Plus the steam off the hot springs form fantastical designs on the surrounding trees.
The few roads that are open are maintained rather well. However, the majority of Yellowstone you'll need to access by snowmobile or snowcat. Tours are available at several locations outside the park and at Mammoth Hot Springs Lodge.