As I understand it, the old school idea of a "winter bike" was for winter training. So it would generally have a longer wheelbase for comfort whilst "putting in the miles", ie. longer rides but no speedwork. It would also have mudguard clearances and attachments. If you're riding in a group in the wet, that would be appreciated. A club may not even have let you come out without mudguards! Nowadays a winter bike just seems to be how cyclists refer to their old one.
A fixed gear is ideal for winter anyway. Fewer parts to maintain and always pedalling will keep you warm. Mudguards, as has been mentioned, are a good idea. Just get clip on/off ones, eg SKS raceblades if you don't want them on all the time. Full length offer more protection though.
As I understand it, the old school idea of a "winter bike" was for winter training. So it would generally have a longer wheelbase for comfort whilst "putting in the miles", ie. longer rides but no speedwork. It would also have mudguard clearances and attachments. If you're riding in a group in the wet, that would be appreciated. A club may not even have let you come out without mudguards! Nowadays a winter bike just seems to be how cyclists refer to their old one.
A fixed gear is ideal for winter anyway. Fewer parts to maintain and always pedalling will keep you warm. Mudguards, as has been mentioned, are a good idea. Just get clip on/off ones, eg SKS raceblades if you don't want them on all the time. Full length offer more protection though.