Recent National Weather Service guidance points to a high near 70°F for San Francisco on August 11, with the marine layer depth and onshore flow creating tight uncertainty between 68–73°F. Persistent cool Pacific waters and coastal upwelling sustain a strong temperature inversion that limits warming, while variable southwest winds and any thinning of low stratus could allow modest afternoon rises. Historical August averages near 69°F provide context, but day-to-day model shifts in boundary-layer moisture and pressure gradients explain why traders assign the highest implied probabilities to the 68–71°F bins. Updated NWS and NOAA model runs expected overnight will likely refine the exact maximum before resolution.