I've commuting year round for close to two decades, you don't need a fancy bike. You don't need fancy tires. For 90% of my winter commuting I'm on wet or dry pavement, in the coldest major city in North America. Four years ago the city began promoting winter commuting, along with a commitment to keep the bike paths clear, and the number of winter bicycle commuters has doubled annually. Enough of them are overweight middle aged ladies, the last type of person you'd suspect to be a hardcore winter commuter, but that's because it isn't actually hardcore. The barriers are psychological, there's a very easy learning curve to overcome, and it comes quite naturally if you just maintain a cycling through the fall. It's also a cure for seasonal affective disorder/cabin fever.

I ride a fixed gear In winter, with the same tires I use in summer. A lot of people are on mountain bikes. Some people are on fatbikes, but that's overkill for basic commuting.