mmm ... more layers? The nice benefit of winter riding is that I don't have to pack extra raingear, as generally the waterproof layer that I use as my rainshell also doubles as my windproof winter layer

Living in the Northeast, my riding does fall off a bit in between December and February. It's mostly just the 25 mile commute and maybe one long ride a month (where long can be defined as 50+ miles). The commute has the advantage of following relatively wide and trustworthy roads, though my routes for the longer rides are definitely more constrained. I found that ramping up training in March and April was a good schedule for doing brevets in May -- so long as I was getting some kind of regular weekly mileage in the winter. However, with PBP next year, the brevets will be starting earlier, so ramp up will have to commence in February.