Official meteorological observations from National Weather Service stations in the San Francisco area recorded a daily maximum of 70–71°F on September 12, 2026, aligning precisely with the long-term September average high of 70.7°F. Mild onshore flow, clear to partly cloudy skies, and the absence of anomalous warming or marine layer suppression kept temperatures within this narrow band, consistent with climatological norms and recent model guidance. Trader consensus at near-100% implied probability reflects high confidence in these verified measurements for market resolution. Only a substantial revision in official data or use of an atypical station could alter the outcome.