This time of year you can get pretty big seas, today running about 17 feet off SF: Northern California NOAA/CDIP Buoy Data
. Coming back from Half Moon Bay
will be uphill and against the current, not good sailing conditions, probably have to motor most or all the way, not a fun trip in my opinion. Suggest you stay well off shore and enter the ship channel at the light station. Don't even think of taking the inshore "channel" off the SF beach. Marine forecast :
Marine Forecast : Weather Underground
My apologies if you already know all of this.