I am also in SoCal (zip 92064), and biked to work this morning, didn't check the temp or wind chill though. Wore about the same as I have been lately, chamois/liner + basketball shorts, smartwool socks & mtn shoes, 3 layers up top: synthetic short-sleeve for sweat, cotton mid-sleeve for layering, synthetic long-sleeve pullover for more layering, and visibility (bright red with reflective patches). The only thing I did different was switch to full-on ski gloves (so warm!) and a sweatband pulled down over my ears, which really helped.

Here's a post on winter cycling from one of my favorite websites, Mr. Money Mustache.

Oh, and a tip my wife read for keeping toesies toasty on the cheap, use a plastic grocery bag as an air-barrier between socks and shoes. Just scissors the surplus off around your ankles. I used to live 26mi from work; I only occasionally bike-commuted from that distance, but it kept my feet warm until mile 20 or so, as opposed to numb toes almost the whole ride, in the chilly SoCal winter dawn.