I've said it before, and I'll say it again: San Francisco summers are weird. They're invariably foggy and windy, sometimes with fluke showers, and often with a spare 90 degree day or two amidst the plethora of colder, overcast ones.
I'm not complaining! I love overcast. I love snuggly. And, when I haven't just straightened the living daylights out of my hair, I even love fog. But it does present a challenge when you're trying to dress "summery" in a place that requires jackets year-round.