I've had some very pleasant moments riding in winter's darkness, but those have usually been well away from rush hour and normal commuting times. Riding in the dark when there's a light snowfall and quiet, empty streets is great. Navigating icy, snowy, narrowed, and rutted streets in the dark and in traffic is not so fun.
Today January is half over and it's our coldest month on average. This weekend we're expected to have the coldest weather of the season with temps reaching close to -20. By virtue of MLK day I won't be riding again until Tuesday when things start to warm up. After that it looks pretty decent with temps in the 20s, - which I consider ideal for winter.
Overall this is shaping up to be a another relatively easy winter. Historically my coldest commutes have been in early February if I remember right but I don't think I'll be breaking any personal records this year.
Within about 3 weeks I'll be spending most of my commutes in at least twilight. Looking forward to it.