Recent National Weather Service guidance and ensemble model runs indicate a high-pressure ridge over the eastern Pacific will suppress the marine layer and limit fog, supporting daytime highs in the upper 60s to low 70s for San Francisco on October 1. This setup favors modest warming relative to seasonal normals but keeps substantial uncertainty around peak values due to variable onshore flow strength and the precise timing of ridge amplification. Trader probabilities cluster tightly across the 71–75 °F and adjacent buckets because small forecast shifts—common within 48 hours of the event—can move the daily maximum across those thresholds, while probabilities drop sharply above 82 °F given current atmospheric conditions. Updated NWS and NOAA model runs through September 30 will provide the next key data points for resolution.