My life's work has been riding to work.
I've ridden my bike to every job I've had since I graduated from college in 1979. I had no idea it would be such a controversial and political activity when I took it up. It just made sense: I got exercise and saved money. Why wasn't everyone doing it?
Whatever else I planned to do and still hope to accomplish, riding the bike is the most effective advocacy I can think of. Be seen on it. People will eventually have questions and ask them. They also take your opinion more seriously when they see you acting on it.
Winter is tough for cycling around here. Even in the warmer, lighter months I understand that many people have to rely on motor vehicles. Sharing the road goes both ways. Motorists do have a big responsibility because their vehicles are large and hard, but bicyclists have to balance their rights against the need to move people from place to place cooperatively. It's a balance more complicated than a few regulations can encompass. I spend most of the winter waiting for the next bike season. If I had only to deal with the weather and light my way through the darkness I could handle it. The vehicles with which I have to share the road create the vast majority of the obstacles. So I journey inwardly.
Winter used to be mountaineering season. Any cross-country skiing I did on the groomed trails where I work was only to build and maintain fitness for excursions to places that were harder to reach. These activities provided good alternative training to relieve the unbalanced fitness and possible overuse injuries a year-round cyclist might suffer. The upper body muscle came in handy for the season of splitting and carrying firewood. Now splitting and carrying firewood forms the majority of my winter exercise. I don't have the right amount of time in the right places in the day to do anything ambitiously athletic or to prepare for any expeditions. Some time after the first of the year I will probably start riding the rollers. I also keep saying I will start walking the path to work in lieu of riding it, but so far I just sleep too late and drive the whole way.
Depending on the amount and quality of the snow I might do a park-and-ski commute on the path. It's used by snowmobilers, so I have to worry about being buzzed by motorheads. It's a lot easier to dive off the path on skis than it is to bail from the roadway on a bike (should I be inclined to do that). In places it would even be fun, although the path follows a valley floor, so it provides no real opportunities to dive down a glade and crank a few turns.
The most practical ski for path commuting is not a very sporty one for fast striding, but conditioning is conditioning.
Skiing depends on a narrower range of conditions than cycling. If I ski in on a cold morning and a wet warm front moves in during the day, it could wipe out the snow completely. The trip back to the car would be a muddy plod. The reverse is also true: I might walk in the morning on bare ground and face a foot of snow in the evening. If the weather goes from dry and chilly in the morning to wet in the evening when I'm riding the bike I just ride anyway. I have fenders. So winter is more finicky than the seasons that aren't winter. It's really easy to abandon self-propelled transportation entirely and go from car to building to car to building, day after day until suddenly you're a waddling doughball facing bike season with no fitness base. That happened to me last year.
I don't make New Year's resolutions. If something is a good idea, it's a good idea. Do or don't do. The date does not matter. Last winter was pretty crappy for a number of reasons. This winter has already delivered woes of its own, with death and illness around town. Quite often there's more to consider than the weather or the traffic when deciding when or whether to go out.