Last week, San Francisco experienced an unprecedented heatwave, marking its hottest week in 85 years. Multiple cities across the Bay Area shattered century-old temperature records. According to the San Francisco Chronicle, between September 30 and October 6, the city’s average daily high temperature skyrocketed to 90.3 degrees Fahrenheit, nearly 20 degrees above the usual. This unusual spike made it the hottest week since 1939 and the third hottest since September 1874, with the all-time highest average temperature in San Francisco being 93 degrees back in September 1939.
Interestingly, data from the Pacific Gas and Electric (PG&E) weather station—located just three blocks from Ocean Beach—showed that coastal areas remained relatively cool, averaging only 78 degrees for daily highs. However, the daily low was a warm 69 degrees, setting a record for the hottest October nights on record.
Cities throughout the Bay Area recorded their highest temperatures in nearly a century. San Jose reached an average daily high of 100.1 degrees, marking the hottest week since July 1905, with a daunting peak of 106 degrees on October 2—the hottest day the city has seen since 1980 and 2012. San Rafael smashed its previous week’s average daily high with a scorching 102.7 degrees, surpassing records set in 1894, and topped out at 107 degrees on the 6th.
Additionally, Santa Rosa, Kentfield, and Napa all recorded 102 degrees on October 6, marking their hottest daily temperatures since 1930.
Meteorologist Nicole Sarment attributed last week’s extreme heat to an unusually warm air mass and the absence of the cool afternoon sea breezes that typically offer relief to coastal cities. With human-induced climate change playing a significant role in global warming, data from the U.S. Environmental Protection Agency reveals that autumn temperatures in California have risen by approximately 3.1 degrees since 1896, resulting in more intense, frequent, and prolonged heatwaves.
Looking forward, weather forecasts indicate that by October 8, temperatures across the Bay Area are expected to drop below 100 degrees, although average temperatures for the week will still remain above normal.
