Onions are somewhat influenced by the soil. The vidalia onions are grown in low sulphur which makes them less strong. The Maui onions are standard short day granex like is grown in Georgia. Since it doesn't get terribly cold in Sacremento, you may be able to plant a similar onion in the fall to overwinter and harvest in the spring. As far north as you are, a walla walla type might do better. There are various new varities like super star and candy that might do very well for you fall planted.

Robert

candy..... mmmm Thanks for the reply! I'll look into these.