National Weather Service observations at San Francisco International Airport and downtown stations recorded a daily maximum of 68–69 °F on May 21, locking in the market-implied outcome. Persistent marine-layer stratus and a moderate onshore flow suppressed solar heating despite mostly sunny skies, keeping temperatures near the seasonal average of 65–67 °F. Light west-southwest winds and the typical afternoon sea breeze further capped any inland warming, consistent with long-term climatology for late-May coastal conditions. Only a significant delay in the marine layer or an anomalous offshore flow could have pushed readings into the low 70s, scenarios not supported by the day’s official data or model guidance.