It is interesting that this comes up today for me. I rode to work today, and this is the coldest weather that I have ridden in (previously I was doing fun rides, and if I started getting cold, I could just turn back). By the time I reached the office my feet were quite cold.
Somewhere I was reading on the web that cold feet can be a symptom of the core body itself getting cold. And as it happened, I felt chilled most of the day at work - I happened to have an extra sweater in the office, which helped a lot. Thus my gut tells me that I need an additional layer of some sort around the chest, and perhaps the feet won't get quite as cold.
The way home from work was much better - it was about 10 degrees warmer in the evening than it was in the morning.