There was only one time in the last two years that enough snow fell that I had to walk most of the way home... Pushing the bike through knee-deep snow on the sidewalk was STILL faster than driving, some of my co-workers almost ran out of gas stuck in endless traffic jams. Probably drivers in Sweden have a better grasp on the snow-tire thing.
The ugly days are the ones where it's sunny but real cold. Cars go at summer speeds, the bike feels like it can barely move.