**Forecasts from the National Weather Service and private models place the overnight low in San Francisco on August 27 firmly in the upper 50s to low 60s, with the marine layer and persistent onshore flow as the dominant controls.** Typical late-August conditions feature a shallow marine inversion that caps daytime heating and promotes radiational cooling under stratus or clear skies overnight, producing minimum temperatures near the long-term average of ~56°F at downtown or airport stations. Current model consensus shows west-to-southwest winds of 10–20 mph sustaining advection of cooler Pacific air, while high pressure to the east limits significant warming or offshore flow that could raise readings. Slight differences among the tightly bunched 56–61°F outcomes hinge on small variations in marine-layer depth, the exact timing of any late-night clearing, and local microclimate effects between the immediate coast and slightly sheltered valleys. Stronger or more persistent low-level winds and thicker stratus would favor the lower end of that range; partial decoupling or reduced wind would allow modest additional cooling or slight warming. No major synoptic shifts are expected before resolution, keeping probabilities concentrated on these near-normal bins.