What does the well dressed cycle commuter wear in winter?

Yeah, I'd focus on base layers, not overlayers. I have one of http://us.icebreaker.com/en/mens-baselayers/everyday-long-sleeve-crewe/101261.html?cts=001%7CG80%7C401&dwvar_101261_color=001 with the matching leggings. Since it's wool, it doesn't need to be washed frequently, and I can wear it day after day without it stinking up. Also because it's wool, it adapts to temperature changes. When things get warm, it seems to cool me, and when things get cold, it warms me.

Yeah, in that kind of not-cold, a shell should do you, and I'd go for one of the lightweight bike ones that's bright. In my (colder) climate I use an LL Bean fleece that includes wind-breaking, and that's usually plenty after the first block or so. I use one of their thin fleece windbreaker hats as my helmet-liner, too, and really like it.

Your fingers will get cold far before the rest of you, so find a pair of gloves that work for you (windproof, very flexible). Since you will only need them while riding you needn't go with fancy leather, though leather would probably work. Also, you'll need a hat. If you use a helmet (as I assume you do), you probably just want something like a watch cap.

I used to bike 3 miles to work in Boston in very similar conditions. I would wear my work chinos or jeans with a shell over them on the bottom. I liked that it blocked the wind and kept me from having to worry about getting my hems dirty from the chain. On the top I'd wear whatever I was wearing to work (tshirt or oxford) a sweater, and a Northface shell. I also had a balaclava thing to keep my head and neck warm. Basically I think you'll be fine in what you're wearing, maybe with the addition of an upper and lower shell to block the wind. I prefer to add shells rather than base layers because the base layers are hard to take off and impossible to zip down if you find yourself getting warm. Nthing that keeping your hands warm will be the hardest and most important thing. I never quite found gloves that I liked so I'd talk to your local bike shop about it.

I cycle in my ordinary winter overcoat--it looks a http://shop.nordstrom.com/s/boss-ciera-collared-wool-blend-coat/3736046?origin=category-personalizedsort&contextualcategoryid=0&fashionColor=&resultback=195&cm_sp=personalizedsort-_-browseresults-_-2_3_A. I ride an upright commuter bike in Chicago and usually, I'm fine riding my four mile commute in my http://www.polyvore.com/transporter_blazer_womens_wool_corduroys/thing?id=12019522. I wear a merino cap under my helmet; usually I wear merino long johns over my tights under my skirt. I rode all through this year's "polar vortex" winter in my regular business clothes and my ordinary wool overcoat. It's true that you don't need to dress nearly as warmly to cycle as you need to dress to stand on the corner waiting for a bus, so I usually carried an additional layer if I knew part of my day would involve public transportation rather than my bike. The hardest part is keeping my hands warm. The only thing that comes even close are lobster mittens, layered over merino gloves. I may have to rig bar mitts this winter.

I should add, I cycle in my ordinary overcoat because I often have to leave my office to go to meetings at BigLaw and my boss would be unhappy at me showing up in those BigLaw offices in something that looks like "cycling clothes" or a ski shell. So I wear my overcoat to bike in.

People are mentioning the dressing less warmly thing, so I figured I'd share the rule of thumb I use: Dress for it being twenty degrees (F) warmer than it is.

N'thing I only have problems over-heating. I'll wear a windbreaker if it's above freezing and a light sweatshirt under it if the temperature's below that (and usually take one or both off after a mile) on top of my regular undershirt and dress shirt (no jacket). I added shields in front of my handlebars where my hands are. Without the wind, I can wear light gloves that breathe and my hands stay a comfortable temperature.

I live in a much colder climate. I like to use a lightweight down-filled vest, worn under the jacket, as my added layer. In your area, perhaps a microfiber vest would suffice. Land's End, REI, Dicks will all sell them.