Persistent marine layer influence and moderate onshore flow from the Pacific are anchoring San Francisco highs near the long-term August mean of 67–68°F at KSFO, the resolution station. National Weather Service guidance and ensemble model runs converge on a daily maximum of 66–68°F under partly sunny skies with west-southwest winds of 10–20 mph, suppressing inland heat advection. Recent observations show no significant warming trend or ridge amplification that would push readings into the 70°F+ range, keeping the 68–69°F bracket at 46% implied probability as the modal outcome. Traders are weighting the tight clustering around the climatological norm, with limited upside risk absent an unexpected offshore flow shift.