It's worth changing to a lighter gearing since riding through snow makes it much harder to pedal. While I rarely ride through snow, I do find it nice to have a lower gearing since I find that the combination of colder weather and wind makes a higher gear undesirable. My cold muscles don't like hammering away just to go like 18 kph into a headwind which makes it feel like -40c.

That's just personal experience and what i've read so far though...