In the summer it definitely rains more than in the winter, but not that much. Sometimes the weather turns bad for some days as you experienced (and as it happened last week). Overall I don't think it rains that much, I can count on one hand the times I had to wear the raincoat on my bike during the last months (I bike every day). Drizzle is bearable in my opinion, but of course does not compare to an always sunny weather.
I prefer much more a changing weather and changing seasons to constant weather, but that's definitely very personal.
Of course there are trade-offs, and you have to go through the winter which in California does not exist.