January is a ways off, but if the conditions are right and the timing works out, you are welcome to split a charter with me renting a charter club boat.
Other choices include swinging by cal sailing (Cal Sailing Club \| Windsurfing and Sailing Lessons \| Berkeley Marina - San Francisco Bay
)and getting some dinghy sailing in. They have stuff going on all the time, and a quarterly membership probably costs less than an average dinner in SF.
For a brief sail, there is also the lake merrit boating center. its a small lake, but surprizingly fun to get a quick sail in. Boating ~ City of Oakland, California
But PM me when you get into town. There are some great days here in January, but it is a little unpredictable.