yes, there is a reliable source for the weather: In the summer months, regardless of what's happening outside of the bay, the wind almost invariably comes up around noon or a little later. It sweeps into the bay and up the delta as well as down the bay, often kicking up quite strongly - up to 20 knots or even more. It's usually strong enough that when close hauled you will want to reef your sails. (The only ones who don't are those who like sailing with the rail in the water.) This is caused by the hot air rising in the valley, sucking in the cooler air over the water. Usually around 5:00 or so it dies down and within a couple of hours it will be almost no breeze at all.
There are a few usual dead spots - in the lee of Angel Island, and also on the west side of Treasure Island.
