No one can answer your question, with certainty, and there are no guarantees. You may skate through, unscathed, with good weather and favorable winds. FWIW - We considered doing this ride in mid-November, and decided to put it off until next year.
You will want to check various weather sites, but this is what I found for Monterey -- December temperature averages: high temp = 58F, low temp = 44F; Average rainfall = 3.41 inches; Average wind speed at 0-9 MPH; direction: East =16%, South East = 14%, North West = 11%, West = 10%.
Expect no more than ten hours of daylight.
I am familiar with San Francisco to Morrow Bay:
(1) San Francisco to Half Moon Bay - lots of places to hole up
(2) Half Moon Bay to Santa Cruz- gentle road but few stores, restaurants, motels, and almost no escape routes to the east.
(3) Santa Cruz to Monterey - lots of places to hole up.
(4) Monterey to Morro Bay - very remote, very rugged, with very few stores, restaurants, motels, and no escape routes to the east until near Morro Bay
(5) No knowledge beyond San Luis Obispo
I do not know if you will be supported, intend to credit card camp, or tent camp. If someone can rescue you, then you will be fine. If not, plan your trip with great care, and keep an eye and ear peeled for weather conditions.
I wish you a happy and safe trip!