San Francisco’s typical summer marine layer and onshore westerly flow are expected to cap the August 11 high near 70–72 °F, consistent with NWS guidance and the August climatological average of roughly 69–70 °F at downtown and airport stations. Model consensus shows gradual morning clearing followed by modest afternoon warming under light southwest winds, keeping the daily maximum in the low-to-mid 70s rather than allowing stronger offshore flow or clear-sky heating to push readings higher. The tight spread between the 70–71 °F and 72–73 °F market bins reflects residual uncertainty in exact clearing timing and boundary-layer mixing, with any earlier marine-layer erosion or lighter winds potentially adding 1–2 °F. Historical analogs and current ensemble runs indicate only a low probability of exceeding 74 °F absent an unexpected shift in the subtropical ridge.