San Francisco weather can be notoriously unpredictable. Neighborhoods right next to one another can have different microclimates depending upon the fog and hills, which can create chilly wind patterns for unsuspecting tourists. The best way to address SF weather is to layer your wardrobe, especially for the post-conference receptions. Although October is traditionally sunny in San Francisco, one can never be certain. You should pack an umbrella just in case, and most definitely bring a jacket for the nighttime weather.