I've always maintained that acclimation is a huge part of it. I start getting ready for January in October. I wear just a little less than I want to, so that I'm on the cool side. Not cold, but a bit chilly. By being cold in the autumn, it helps me stay warm come winter.
Haven't closed my pit-zips yet.
I agree with this, although I haven't been riding with open pit zips for a while.
I had a rather nice ride this morning. 0-deg F, but no wind, and it was *sunny*. I'm hoping I can ride again tomorrow, but my knee is acting up a little. We'll see....