Sunny and relaxing "hidden gem"?

Northern Californiain Feb can be unpredictable. If you visit the monterey peninsula I love the Elkhorn Sloughestuary boat tour. If you visit Sonoma, Petaluma has a beautiful downtown, The Cottage Nursery, French Marin Cheese Factory tour and farm trail tours, wineries, and the Osmosis Day Spa Sanctuary. For guaranteed sun, SoCal is the better bet, and Palm Springs has great modern architecture.

One word. Yosemite. Few places have made my jaw drop, but Yosemite National Park did exactly that.

This isn't hidden but my favorite place on earth is Carmel By the Sea.

Sonoma.  It's a bit less expensive and a lot less snobbish than Napa.  There are plenty of good wineries in the area, and downtown Sonoma has several good attractions, including Mission San Francisco Solano State Historic Park and the Mariano Guadalupe Vallejo house.  

In February, the best sun break would be in Southern California, in any of the Coachella Valley resort cities: Palm Springs, Rancho Mirage,  Palm Desert or Indian Wells. The more 'hidden' place would be Borrego Springs

My experience of Northern California in February is that it was rarely sunny or warm.  YMMV