Sure, the water is cold and you probably will need a wet suit. But Anchor Bay Beach is a fun place to ride the waves. David Wayne Floyd recently photographed a fellow with a boogie board enjoying the waves.
Here's a link to a photo of surfing at this beautiful beach: http://www.mendonomasightings.com/2011/05/20/surfing-on-the-mendonoma-coast/
Thanks to David for allowing me to share his photo with you here.