Someone else can probably answer better than me, but I also live in the Bay Area, and my feelings are that it is too cold outside for seedlings but that established plants should be fine, so my advice would be to start them indoors if at all possible, til they get big enough that the cold will just make them go a bit purply in the stems and not outright kill them. I have a couple bagseed photos that I currently have inside on 20/4 that I am going to see if I can get to flower outdoors. Even tho the days are getting longer, I think the dramatic drop from 20/4 will be enough to get them to bloom. I had been thinking about the cold because our last frost is technically sometime in march, but it usually stays above 40 at night never really gets below 30 so I think fully vegged plants will be fine if it dips down there. So my advice to you would be, temperature wise, you'll be fine as long as you start them indoors. One not of advice though, and mind you it could be wrong since I've never grown autos before (I currently have two going, but I've not finished a grow with them), but you may be looking at a pretty heavy yield reduction flowering autos outdoors with less than 12 hours of light, AFAIK they like longer hours. But I could be totally wrong, I'm sure others will chime in.