Recent National Weather Service model guidance highlights a persistent marine layer and moderate onshore flow that continues to moderate daytime heating in San Francisco, positioning the August 12 high most likely in the 68–71°F range and aligning with the market’s leading implied probabilities around 70–71°F. This coastal pattern, typical for mid-August, features low stratus and fog that delay solar warming until afternoon, when temperatures often peak near the long-term average of 70°F. Ensemble runs show limited upside potential from stronger warming, while recent observations confirm highs remaining in the upper 60s amid sea-breeze reinforcement. Traders appear to weigh this established meteorological setup against the low historical frequency of exceeding 75°F in the city during similar marine-influenced periods.