I used to commute year-round in Michigan. My commute was short -- just shy of 2 miles -- and the time spent outside in the elements was roughly similar to what I'd have spent walking in from the employee parking lot. In addition to the commute, I rode when I could on weekends.

Then I moved. Wife insisted, dragged me kicking and screaming. Now the commute is 11 by car or 14 by bike. The "by bike" route includes three unavoidable choke points which would be extremely dangerous on a bike, and the morning commute would be in dark for 2/3 of the year. So I no longer bicycle-commute. And although there are a couple of low-traffic routes I could do in the winter, the bike's put up and I really have a problem getting motivated.

So, since I moved, not much mileage in the winter. Instead, I enrolled in a lap swim class at the local CC. Unfortunately for me, the college recently decided that its primary mission isn't to provide classes to the community; it's to make money. Swim classes don't make money. So the pool has now been filled in so they can have another food court. Don't know yet what I'll do for this winter.