Lovely and warm still, but to be honest I still end up sweaty & toasty in the depths of winter after a few miles of cycling. It can be nippy to start with, but 10 mins later it's definitely not!
The only thing that's driven me onto the bus a little more during the winter months over the last few years is the ice. First few years were fall-free, but after a few icy offs, and more than a few heart-stopping slides, I'm a little more reticent about risking it. If my route is well-grittted, it's fine - but some of the unavoidable off-road cyclepaths used to be sheet ice for weeks! Last year I was off the bike for a few months, but made up for it by buying and using a turbo to keep me in shape and keep my backside saddle-ready.