This comment by Mark Albright at the UW is pretty interesting since WE are having such a great late summer and fall!!!
"Downtown San Francisco has just endured the coldest September of the past century with an average temperature of 58.1 F, which beat out the previous record set 50 years ago (1962) of 58.3 F. The temperature failed to reach above 70 F all month until the final day (Sunday) when the temperature soared to 84 F! The September record high temperature for downtown San Francisco is 101 F set 41 years ago on 14 Sept 1971. I can vouch for that as I was in nearby Healdsburg (60 miles N of SF), where the temperature reached 114 F on 13 Sept 1971 and 113 F on 14 Sept 1971, the warmest temperatures I have ever experienced"