The National Weather Service climate summary for San Francisco International Airport recorded a minimum temperature of exactly 56°F on September 7, 2026, reached around 6:15 a.m. local time under clear to hazy conditions with light winds. This value matched the 1991–2020 normal low for the date and aligned directly with the 56–57°F bin that captured full market-implied probability. Early-morning METAR observations showed readings in the mid-50s before gradual warming, consistent with typical September marine influence and the absence of strong offshore flow or anomalous cooling. Only a substantial revision to official station data or a shift to a different reporting site could realistically alter resolution.