San Francisco’s highest temperature on August 6, 2026, is expected near 70–74 °F under the influence of the marine layer and persistent onshore flow that moderates coastal readings during the broader California heat wave. National Weather Service point forecasts and recent model consensus highlight light west-southwest winds, possible morning haze or patchy low clouds, and highs centered around 70–72 °F at downtown and airport locations, aligning with the market’s heaviest volume on 72–73 °F. Stronger sea breezes or increased stratus could cap readings in the upper 60s by enhancing evaporative cooling, while any temporary weakening of the onshore gradient or clearer skies could allow brief warming into the mid- or upper 70s. Historical August averages near 69 °F and the narrow spread of current guidance underscore the modest upside risk reflected in lower-probability bins above 76 °F. Updated NWS briefings and afternoon model runs remain the key near-term catalysts.