In my experience (about a dozen transits through that area, mostly at that time of year), cool weather is normal on the first day into or out of either Los Angeles or San Diego so bring a light jacket or a sweater to wear if you go out on deck. There may be some swells, but nothing that I would regard as rough.
Then again, my idea of "rough" is 30' seas with 10' to 12' waves rolling down the whole length of the flight deck. Your mileage may vary....
We're booked from Ft. Lauderdale to L.A. Panama Canal in December...(on the Summit!) what can we expect weather wise??????