Recent National Weather Service guidance and ensemble model runs from GFS and ECMWF point to modest overnight cooling under a variable marine layer and light onshore flow, keeping the lowest temperature at San Francisco International Airport clustered in the mid-to-upper 50s. Persistent coastal upwelling from the California Current maintains adjacent Pacific waters near 55–58°F, while frequent stratus and sea breezes limit radiational cooling and suppress extremes. Minor differences in boundary-layer moisture and wind speed across model spreads create the tight probability distribution across 54–59°F bins, consistent with typical late-August climatology that rarely deviates far from the mid-50s baseline. Updated forecasts and observational data over the next 24 hours remain the key variables that could shift final readings.