I live in Montana where there has been snow on the ground now for about 2 months. My winter activities typically include, in roughly this order of preference

- backcountry skiing - that is, hiking up mountains and skiing down them and repeating the process as long as the snow is really good. A day can last anywhere from 3 to 8 hours.
- skate skiing (cross country skiing)
- swimming (which has been difficult to get into but overall a very good workout)
- spin classes
- or, like the other day when it warmed up to 40 degrees, I went for a two and half hour road ride! I've also begun a routine of core workouts to prepare for a season of mountain bike racing.