Current National Weather Service and NOAA forecast guidance points to an overnight low in San Francisco on August 22 in the mid-to-upper 50s, shaped by a persistent marine layer bringing stratus clouds and onshore flow that limits radiational cooling. Ensemble model spreads from the GFS and ECMWF show temperatures hovering near 56–61°F, with small differences in fog timing and wind speed determining whether the minimum falls into the 56–57°F, 58–59°F, or 60–61°F bin. Historical August climatology places typical lows around 55–58°F, but recent clear-sky periods have allowed slightly warmer readings, keeping probabilities tightly clustered and responsive to the next model update cycle.