It all depends on the type of winter. I'm no stoic, so cycling 50 mins at anything below -10C is out as is forcing at track though deep snow. That said Uppsala winters have temperature that hover around -5 to +2 and studded winter tyres are standard kit for both cars and bikes.
The biggest challenge on my commute will be on the dark mornings and evenings as I have 15 km of totally unlit forest track. I'm considering extra lights for my bike, since, quite litterally I have almost cashed with roe deer, elk and wild boar.