Well, a westerly wind would indicate blowing in to the ballpark. San Fran is the windiest ball park in all of the MLB. That wind will turn Homers into singles tonight. I've seen it many a time in that ball park. Is what it is. As the inning progress, however, the air will open up. Out west, our winds stay prevalent until about sundown when they die down - in San Fran primarily blowing in directly off that giant water mass in the Pacific. A 7-12 mph wind, however, will still easily gust to 20 mph out this and that way.