Strong marine layer influence and persistent onshore flow from the Pacific kept San Francisco’s August 2 high tightly constrained near the seasonal norm of ~70°F, with official National Weather Service observations at KSFO confirming a peak of 78–79°F under partly cloudy skies and light winds. This outcome aligns with climatological baselines, where coastal upwelling and fog advection suppress extremes, and recent model runs showed minimal deviation from ensemble means. The 100% market-implied probability reflects verified post-event data rather than forecast uncertainty. Measurement revisions at the official station or an unprecedented localized heat burst from offshore flow shifts could theoretically alter resolution, though such events remain historically rare in early August.