When the roads are clear. This includes residential roads and they take forever to clear. Riding main arterials is not my idea of fun. I will ride them when I commute and that is all.
Commuting is not that amusing this time of year for me. It is below my temperature tolerance.
However, I am going to make an attempt to commute a couple times a week in the new year.
With snow and such I prefer riding the trails on my MTB.