Here are the layers I wore to bike in the cold weather (5 F). This isn't my coldest weather outfit.
I'm going to yoga class, so I'm wearing stretch pants and shirt; then thick wool socks and a wool hoodie sweater.
The hood is on, and a fleece sweater/jacket. So that's three layers on my torso, and one on the legs.
Coat, warm snow/ski pants, warm boots, liner gloves, and balaclava.
So that's now 2 layers on the legs, 4 layers on the torso, and 2 layers on the head.
Add a helmet (covered with a gortex cap, great for keeping rain and wind out!) and goggles (so 4 layers on the head?) and thick gloves (2 layers on the hands). The gloves are not warm enough. I just ordered a big pair of warm mittens (ugh, expensive too). I hope they do the trick. The goggles are amazing for warmth. A small part of my nose is exposed and this won't do if it gets any colder or windier. Too bad because this setup causes no fogging on my glasses or goggles. I have another face mask that covers my nose so that will come out soon.