**Official National Weather Service observations confirm a daily maximum of 66°F at Chicago O’Hare on October 14, 2026, placing it squarely in the 66-67°F bin that now holds 100% market-implied probability.** After an unseasonably warm mid-October period that produced a record 88°F high on October 12, a cold front shifted the region back toward seasonal norms. The NWS climatological summary lists the October 14 maximum at 66°F (two degrees above the 1991–2020 normal of 64°F) with the peak occurring mid-morning before steady cooling under increasing clouds and northeast winds. This reading aligns with independent station data and falls well below the date’s all-time record of 89°F set in 1975. The near-certain market consensus reflects the finality of verified post-event measurements rather than forecast uncertainty. Only a substantial revision to the official record—such as a corrected station reading or use of an alternative site—could realistically alter the outcome, an event with negligible probability given standard NWS protocols.