April to Sept , lucky few windy days in Oct. Check out Boardsports webcam and their wind station charts. At Alameda, in May , August, not that cold. You may be even comfortable in shorty wetsuits. Other than that 4/3 never hurts.
~ April through ~ Sept. You'll need a 4/3 year round. Water temps vary greatly depending on where you are in the bay or if you are on the coast?
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