Most people screw up their noses when I let it be known that I commute daily by bike all winter! They further contort their visages when I explain I train all winter.
They ask why! Simply I prefer to ride. If I have to commute to by car or motor scooter it just does not set me up right in the morning.
So here is what I wear, other than a helmet, cycling gloves and footwear suitable for the pedals of the bike I will ride. Sometimes it's cycle shoes and cleats, most often my flat sole slip on winter shoes. Either way I pedal hard! (gets the temperature up!)
On the bottom!
Usually everyday trousers. If wet these Groundeffect ( http://www.groundeffect.co.nz/products/ ) hydrofoil 'Helter Skelters' go on and I change at work.
Up top I prefer this red light weight fleece cap. Needed now-days due to scalp exposure! Better days a Buff of various forms. http://www.buff.eu/index_eu.php?l=en&p=USA
The highvis ankle strap is worn everytime with trousers and doubles as a safety feature in the dark.
Finally, the agent orange 'Flash Gordon' full length heavy hydrofoil jacket. Most excellent, often ride home at night uphill with just this on over a business shirt. This too packs into small rear sized 'bag'.
Near the rear I use one of these both in the dark and during the day. The flashing keeps the drivers at bay.
Overall I keep an eye on the weather and just layer up to ride. Below 8 degrees C I wear wool next to my skin. Snow doesn't stop me but icy roads will!
Sweet riding ........ all winter long. Eclectically Cheers.