**Persistent marine layer influence and onshore flow from the cool Pacific are anchoring trader expectations for a moderate high in the mid-to-upper 60s on August 14.** Official National Weather Service guidance projects a partly sunny day with a high near 67°F, consistent with the market’s heaviest concentration on the 66–69°F bins (combined ~66.5% implied probability). A deeper marine layer and upper-level troughing have kept coastal temperatures below seasonal norms, with stratus and westerly winds limiting afternoon warming. August climatology for San Francisco centers on highs near 68–70°F, but recent model consensus from NWS and AccuWeather shows limited clearing potential and continued onshore advection, favoring outcomes clustered around 66–69°F. Traders are weighting these ranges most heavily because the current synoptic pattern—persistent low clouds, moderate west-southwest winds, and no strong offshore flow—matches historical analogs that produce highs in this narrow band. The lower tail (below 64°F) and upside (70°F+) carry smaller probabilities, reflecting the low likelihood of either stronger marine suppression or rapid clearing under present conditions. Updated NWS discussions and morning model runs will be the next key inputs likely to refine these market-implied odds.