I commute to work. I leave home at 5am, get to work by 6:30. When I lived in Santa Clarita, some mornings were 30--32 degrees. This is what I wore on those days...

• Long-fingered gloves (still not warm enough)
• Leg warmers (not just knee-warmers)
• Thermal bib-shorts
• Base layer
• Arm warmers
• Short-sleeved jersey
• Jacket
• Headband (covered the ears)

Obviously, on warmer days, I didn't have to go to these extremes. (Coming from Upstate New York, it's laughable calling it "extreme".)

Where you live in SoCal can make a difference. Closer to the ocean, the air-temps don't dip as low, nor do they get as high in the summertime.

Then, for the ride home at 3:30pm, it had warmed significantly so I only wore...

• Bib-shorts
• Arm-warmers
• Jersey

I left the base layer at work (picked it up for washing at the end of the week) and used another the following day. I then stuffed (layered, really) everything else in my jersey pockets. Some days were cool enough I could get away with wearing the jacket, but fully unzipped.