Many of my newbie bike commuting friends ask me about clothing for cool, cold, and wet weather. First of all, this is not an exact science. Trial and error is the best method, and what may be perfect for one person may be too warm or too drafty for another. This is just a quick post and I can go into greater detail later. But, this morning it was 50 degrees, light rain, and about a 15 mph north wind. My commute takes me west and north, so I had a headwind for much of the ride.
Starting from the bottom, my clothing consisted of: regular mtn. bike shoes, midweight wool socks, knee warmers, cycling shorts, glove liners, fingerless cycling gloves, a long sleeve jersey, Pearl Izumi Barrier Select jacket, cycling cap, and of course a helmet.
I overheated just a bit with the protection of the waterproof jacket. Other than that this was pretty good. If it had been about five degrees cooler it would have perfect.
Try lots of combinations to find what works for you. With the right gear though, you can ride comfortably in just about any conditions.