Sf in the winter is better than SF in the summer
That said. You need to keep and eye on the weather and expect HWY 1 to close. Expect to need to fine indoor accomidation. Expect the weather to be too bad to ride due to high wind and/or no visiblity.
I'm actually planning on possibly doing a week on the coast this winter because I'll be getting by frame back from warranty and any coastal CA weather beats Minnesota in Dec/Jan.