I live in Novato with approximately the same conditions, at least the lows are about the same. My ginger never completely dies with the cold, but during a cold winter (like the one before last) it will die back to the ground and then return from the roots when it warms again. Ginger generally takes two seasons of growth to flower. I currently have some flowering as last winter was fairly warm. Hope this helps.

I'm in Houston 9b. We winter our gingers over in the ground. The trick seems to be to plant them somewhere that doesn't get too wet during the winter.

I meant to say 8b not 9b, it's been a long day.