**Trader sentiment for San Francisco’s August 9 high temperature centers on the city’s persistent marine-layer moderation, with 75°F or below holding the highest implied probability at 40%.** Long-term August averages place daily highs near 69–70°F, rarely exceeding 79°F, and current long-range guidance from sources like AccuWeather and the Old Farmer’s Almanac points to a warm but not extreme coastal pattern for the first half of the month, with highs generally 65–75°F and limited inland heat spillover. Key drivers include the strong onshore flow and typical summer fog or low stratus that caps daytime warming along the immediate coast, preventing the triple-digit interior heat from reaching the city. Recent model consensus shows no significant ridge or offshore flow that would allow temperatures to climb into the low 80s or higher on the 9th, keeping the bulk of probability mass (over 85% combined) below 82°F. Minor upside risk remains if the marine layer thins unusually or winds turn more northerly, but forecasters currently see only a low chance of that occurring by the resolution date.