Recent National Weather Service and model guidance for San Francisco on September 28 points to a daily minimum near 55–56°F under persistent marine-layer influence and moderate onshore flow, aligning closely with the 1991–2020 climatological average low of 55.5°F. Recent observations show overnight lows holding in the mid-50s amid stable high pressure and light winds, with no incoming troughs or offshore flow to drive extremes. The closely matched market-implied odds on sub-45°F or 64°F+ outcomes reflect trader emphasis on tail risks from forecast uncertainty, such as potential shifts in the marine layer depth or wind patterns that could alter the minimum by a few degrees, while the 24% probability on the 56–57°F bucket captures the narrow central tendency. Final model runs and NWS updates through Monday morning will likely refine these probabilities ahead of resolution.