In December, it will be cold for this part of the world. As low as the low-40s in the morning. There may also be fog. If the sky is clear, there will be fabulous sunshine, though cool air during the day. If it is cloudy, it will be a bit cooler.

If you are unfortunate and it is a time of rain, it can be bad. Strong winds and rain all day, some of it hard. It is a bit of a crapshoot. If it makes any difference, we haven't had any rain (in SF) yet this year and the weather has been beautiful.

As mentioned above, Hwy 1 will have a narrow, if any, shoulder. You MUST ride with a mirror and be prepared to pull over when traffic dictates. If you don't normally ride with a mirror (why?), then you will be a fool not to get one for this ride.

As I mentioned previously, the wind comes from the north, especially in the afternoon near the coast. During storms, it comes from the south, usually. Best to get out early and be at your destination before the wind picks up.

This is a nice area to ride through. Be careful and have a great time.