I'm in Edmonton, which sounds pretty similar to your climate. Except for those few -40 days I've found winter biking to be fairly comfortable once you get moving.
In my experience you don't want to be using a bike lane after heavy snow anyhow; they often don't get plowed. If you can take residential roads you're pretty safe (and studded tires really do make a HUGE difference).
But yeah, you don't want to be on the road with cars going 80km/h - I wouldn't be comfortable doing that every day in the summer, either.