Table showing how often cities reached certain temperature thresholds in October. 20% of years in San Francisco reached 90 degrees or higher at least once. By contrast, only 0.7% of years had at least one day reach triple digits. In Oakland, 38.9% of years reached 90 at least once in October; 3.7% of years hit 100 at least once. In San Jose, 44.3% of years reached 90 at least once in October; 0.8% of years hit 100 at least once.
The downtown San Francisco site spans 150 years, though two years are missing October data. The Oakland Museum site spans 54 years, with nine years missing October data. The San Jose sites span 131 years, with 13 years missing October data.