Rode in this morning with the thermometer showing 33 degrees, the coldest ride that I have done to date. With the colder weather, I added a second layer of gloves (thin skiing gloves with my padded cycling gloves under) and a second layer of pants (sweatpants underneath my khaki pants, over my tights). The extra gloves were perfect, my hands weren't cold or hot. The pants were entirely too much, and my lower body was sweaty after only about a mile.
So I rode in on the coldest day yet, and sweat the whole way in. O well, this is how you learn!
And for the record, being too hot and sweaty was way worse than being a little cold.