Recent National Weather Service forecasts and ensemble models indicate San Francisco overnight lows in the upper 50s on August 23, reflecting persistent marine layer influence, moderate onshore flow, and typical August coastal cooling from the Pacific. Cloud cover extent will modulate radiative cooling overnight, while variations in wind speed affect boundary layer mixing and dew point depression. Historical averages near 56°F provide context, yet model spread in exact minimum timing and local microclimates creates the tight clustering of market-implied odds around 56–59°F. Updated model runs and NWS briefings remain key near-term catalysts for any shifts.