When the air temperature was less than or equal to 32, I used several articles of clothing. Most of my cold weather rides were after-work, recreational rides in darkness. You may find that for the same air temperature, the presence of sunlight makes a difference in the clothing one wears.

1. The outer layer was always a wind jacket, regardless of anything else I was wearing. Cold air has a way of cutting through just about anything except a wind jacket.
2. I wore a smart wool neck gaiter which kept the cold wind from getting in around my neck.
3. I wore a balaclava which I put on over the neck gaiter.
4. I wore a polyester, long-sleeve T-shirt, fairly loose fitting, next to my skin. It's a BCG that I got at Academy Sports.
5. I wore a medium-weight base layer under my jersey and over the polyester Tee. The one I liked the best had really long sleeves and had thumb holes in the sleeves so that the sleeves stayed down on my arms and went under my gloves. I got this base layer from L.L. Bean. Given that the sleeves stopped around my knuckles, there was a good air seal from my gloves all the way up my arms.
6. On the hands I wore a pair of smart wool gloves liners topped off with lobster mitts or long-finger gloves, depending on how cold it was outside.
7. On the feet, I wore a pair of sock liners, a pair of Woolie Boolies, and perhaps a pair of heavy wool socks over the Woolie Boolies. When the temperatures got around 25 or less, I would add chemical toe warmers, the type that adhere to one's socks.
8. For lower temperatures, I wore wind-front tights, although they weren't my favorite. They worked at keeping the cold air from getting to my legs, but they bound me up, and it was more difficult to pedal. For really cold (for me), I would wear a medium weight base layer under the wind tights. Then, I was really bound up.
9. On night rides, I wore a pair of clear plastic safety glasses to keep the cold air away from my eyes as much as possible.

I am somewhat of a cold-weather wuss; therefore, compared to others, I probably over-dressed. Based on the layers I used, I could unzip things if I started getting too warm.

It took a few years of experimentation to get everything right, but I was able to ride down to 13 F and survive.

OK, I just looked at dalava's post, and forgot to mention the skull cap covering the ears and some toe covers for the shoes.