Do you have Yeti/Sasquatch/Bigfoot/Harry and the Henderson's type bike? Or skinny tires and determination? The commute is about 45 minutes in the summer, so in the winter that's a long time to be cold.
Fixed gear, skinny tires. I'd probably be better off with cyclocross tires, but if you're optimizing for what you're going to be riding on 90% of the time, for winter commuting 90% of the time it's dry/wet pavement or hardpack snow. If the fatbikes give people confidence to ride in winter, more power to them, but personally I think it's overkill.
For the cold you've got to keep your extremities protected. I've got big dumb loose fitting mitts that slide on and off easily, and really warm socks. For my core, though, sweat is more an issue than freezing your ass off. If you dress to be cozy for the first 5 or 10 minutes of the ride, you'll be sweating once your blood gets flowing.
When you are working hard -30 isn't that cold. I haven't biked in that, but I have ice skated - a light sweater was all I needed to be comfortable. Exercise generates a lot of waste heat.
The only cold problems I have with long distance biking in cold weather are caused by poor circulation in my hands and feet. I inevitably get too warm in my core within 15 minutes of commencing biking and start unzipping my outer layer. To keep my head warm, a balaclava and helmet suffices. It's the cold hands that are the worst though; even in thick gloves they still get too cold. I might have to start trying chemical warmers.
I have similar problems, but experimentation suggests that gloves can easily be too tight, esp. at the wrist, and that interferes with circulation. I pretty much always buy XXL gloves now.
Thanks, I should look into that. Hands getting cold is really the biggest problem for me. Those same gloves work fine for warmth when I'm walking, but it's the holding onto handlebars that restricts circulation to the point where they get too cold.
Note that this is only really a problem below -5C or so; at "merely" freezing I can manage.
