Around here (SF Bay Area) anyone commuting in the winter is a bit of an oddity. I kinda like it as it thins out the late season wannabe's. I go year-round, but truth be told, I'm not so sure I'd be game for a year-round commute if it included sub freezing temps for days on end. I do, however, enjoy the solitude of a quiet, rainy ride in the wee morning hours. To me it's almost primal, like staring into a fire. Odd, I know.
Much respect for those that opt out too. There's no shame in bowing out for the season. Primarily because it assures you'll be able to be back next season. It's quite reasonable to expect anyone to avoid risky situations, why would dangerous winter conditions be any different? If it doesn't feel right, don't do it.
-Kedosto