No, it does not snow in the valleys, it only snows in the mountains and every so often it hails in the valleys but it does not snow.
Usually around late November or early December.
Yes, sometimes the weather gets cold enough to snow. Most of the time it just melts when it hits the ground, but occasionally we'll get a few inches. The last I remember where I live, Modesto, is...
About 13", although there were reports of about 20" up around Quincy.
Yes