I think it depends on if you're a hardcore biker and can brave the literally icy winds. I don't have a lot of cycling experience, so I didn't even try it. My boyfriend is from Seattle, where it's much more hilly than here, and finds it easy to cycle here even in the winter because it's so flat. He wears like a ninja mask made for cycling in the winter and a lot of warm layers. So I guess it depends on your experience and desire. It won't kill you, but it'll definitely make you tougher 🙂
I'm going to start biking this spring/summer in hopes I'll be experienced enough and psyched up enough to continue through the winter.
If you know about bike stuff and want to talk to someone else who knows about bike stuff in Kalamazoo, I'd be glad to put you in touch with my boyfriend!