So far there have been at leat 2 LOUD thunder rolls, the air has a distinct mid-fall feel to it and rain is still possible if not imminent in SF and around the Bay Area. Area rainfall for September is extremely light, averaging below .6 inches everywhere, some places seeing only .1 inches. Rain is definitely a plus for cleaning off roads, sidewalks, and structures from accumulated build-up during a long dry period and plants and trees get a nice dose of perfectly pure ocean-generated rainfall. But really, it's the thunder, which claps about 20-30 times a year, that is a pleasant surprise. We may even get a glimpse of an elusive Bay Area lightning strike.
Overall, however, we SFists are starting to wonder if it's about time to turn in this September "summer" for one that is actually warm more than a couple days in a row. September and October are what we all reminisce about - the months when the fog is at bay (or at ocean I should say) and the sun is still dominant. Nights are still long and days are warm. So far we've seen very little on our return for putting up with fogged out August and July and a rainy season that pushed into June.