I commuted for an entire winter one year. That doesn't sound like much, but in North Pole, Alaska it gets chilly. Both my wife and I rode all winter although we drew the line around -25F. We had a chart that we used and wore different clothing every 10 degrees of temp. We wore polypro or a variation of it next to our skin - some mixture of thin and thick layers. Over that we wore a reasonably tight - but not very tight jacket that had windproofing on the front only. The back was not windproof at all. That was the key layer. Down to about 0, we wore nothing over that jacket. After 30 min of riding we would stop and brush each others back off to remove the frozen sweat. Under 0 we would add another windproof jacket over that layer. That jacket was somewhat loose and had no more insulation. Our warmth came from how many base layers we used. We could take off the outer layer and brush the inner layer free of frost. We used poggies on our bikes and medium weight synthetic gloves that were plenty warm inside the poggies. We kept very warm gloves in our panniers in the event of a breakdown, along with a very warm jacket for the same reason. We had big, warm mukluks for boots. No clips or peddle attachments. A balaclava under the helmet was used. We learned we had to start out so underdressed we were quite chilly the first 10min or so, otherwise it required us to stop and remove a layer. Our pants were one or two layers of base polypro and an outer layer of windstop front/nonwindstop back pants. The key is the outer layer that has no windstop on the back side. If you are riding with some effort you WILL get sweaty inside, no matter what. I suppose you could ride slowly and not sweat but then I doubt you'd stay warm. We kept work clothes with us in our panniers. I just took deliver on new Nokian 294's for this winter. We don't commute any longer (retired) but we'll still do some winter riding and probably flake out around -10F cause we are wimpy as we close in on 60. I'm heading to the deep South (Anchorage) to ride the Resurrection trail this weekend. Cross your fingers for me. It will be a difficult challenge for me at this point. Just remember to have clothing to put on in the event of a breakdown. Oh... a small cotton towel to dry your skin off in the event of a breakdown is also a big help. You don't have to strip naked, but just being able to get some sweat off you is a help.