Official National Weather Service observations at Chicago O’Hare recorded a minimum temperature of 66°F on August 22, 2026, reached at 6:32 a.m. CDT under clear skies and northwest flow. This value sits just 1°F above the 1991–2020 climatological normal of 65°F, aligning closely with the dominant market-implied odds of 95% for the 66–67°F bin. Dry conditions and modest overnight radiative cooling under light winds produced the observed low without significant deviation from model guidance or historical analogs for late-August high-pressure regimes. Only revisions to station data or alternative measurement sites could realistically alter the recorded minimum, though official preliminary reports already confirm the outcome.