Wow. I rode my fixed gear to work yesterday. Actual temp was 22F when I left for work. The ride home had me at 8F. As long as it is clear, not raining or icy, I will ride. I have ridden to work in single digits with the wind chill near 0, during the day. At night, when I come home, it is quite a bit colder. I invested in quite a bit of gear for the winter riding, so I am somewhat comfortable. Giro snowboard helmet with ear covers, Pearl Izumi head cover, Oakley goggles, Seirus half balaclava, North Face windproof gloves, Seirus glove liners, Novara windproof/waterproof jacket, biking tights, shorts to go over them, a chamois, Smartwool thick wool socks, and Specialized Defroster waterproof/windproof SPD boots. I hate riding in all that gear, but I hate not riding even more. I prefer a t shirt and shorts with sweat dripping off the end of my nose and my back soaked from my bag, but I will have to wait a few more months for that.