Spend a winter in Duluth, Minnesota or even Chicago, Illinois and get back with me.
We are having a cold spell here in the Bay Area also. Johnboy is lucky because he is in the East Bay. I am only 5 blocks from the beach so it only got down to 42 degrees F.
Matt D is right, its Christmas time and it's supposed to be cold in the Northern Hemisphere.
The best thing to do is stick a log in your fireplace, make a glass of egg nog & brandy and listen to your favorite Christmas tunes. The Carpenters "Christmas Portrait' is one of my favorites.
The dry conditions with no clouds to keep the daytime heat in at night is the reason for the cold nights. Rain is expected this weekend. Expect a lot of brand new SUVs flipped over and in the ditches this weekend.