Recent National Weather Service guidance and ensemble models point to a highest temperature of 65–68°F in San Francisco on September 16, with the marine layer and persistent onshore southwest flow limiting daytime warming along the coast. An upper-level low drifting into northern California has introduced cooler 850 mb temperatures and increased low-level moisture, favoring morning clouds that clear only partially by afternoon. This setup aligns with the near-even market split between the 66–67°F and 68–69°F bins, as small differences in boundary-layer mixing or wind speed could shift the daily maximum across that narrow threshold. Historical September averages near 71°F provide context, yet the current pattern favors readings a few degrees below normal. Updated short-range model runs and the next NWS forecast discussion will clarify whether any late-day clearing pushes readings toward the upper end of the leading outcomes.