Depends how fast you go...
It's about 80 miles by the time you mess around with the kelp off Pt. Loma. The good news is the winds are generally favorable heading south. You'll get a little boost from the current too. I'd plan on 12-13 hrs. at 6.5 knots if you can make that speed consistently. You might be able to do the whole thing in daylight this time of year but it will be close. You could always duck into Mission Bay if you want, it's about 3 hrs. from there to San Diego Bay the next day, makes a good stop over... Have fun!