I live in Wisconsin in a 3 college town.
People ride bicycles and mopeds year round here***, something you never saw until a couple years ago. Once a few nutjobs started doing it, it was wide open. Two wheels were everywhere, with every generation.
I'd say our typical climate change winters (the five years prior to this last one) saw temps mostly between 0-20 and occasionally 15-35, with the really cold stuff being a couple of two week stretches.
If you aren't going to ride on snow and ice, I say go for it with out too many reservations. You'll have to understand that your tires aren't going to grip the road the same. They won't have heat generated suppleness. You could go down a lot easier, so be wary of that. In addition, the pavement itself will have different winter characteristics, and silt and stuff.
For me, the biggest problem is staying warm. I came to motorcycles after a lifetime of endurance sports- I'm used to generating my own heat. It's simply a question of the right gear. People ski and do all sorts of stuff at high speeds in the cold. The gear is out there. Buy what you need and enjoy your ride. Be a pioneer! :cool:
***[This winter sucked big time with 12 feet of snow and four months of 20 below zero weather.... aside from THIS MOST RECENT Winter.....people do that here. Enduros too.]