Current National Weather Service and private model guidance indicate overnight lows near 56–57°F for San Francisco on August 29, driven by the typical late-summer marine layer and persistent westerly onshore flow that advects cool Pacific air inland. This suppresses radiational cooling under partly to mostly cloudy skies while limiting daytime heating that would otherwise raise the subsequent minimum. Historical climatology shows average August lows near 56°F at downtown and airport stations, providing a baseline traders reference against short-term forecast spreads. Minor differences among 56–57°F, 58–59°F, and 60–61°F outcomes hinge on exact wind speeds, marine stratus timing, and any high-cloud interference with nocturnal cooling; stronger breezes or earlier clearing could nudge readings a degree or two higher, while denser fog favors the lower side of the distribution. No significant synoptic shifts appear imminent before resolution.