Official National Weather Service observations at Chicago O’Hare recorded a maximum temperature of 67°F on October 2, 2026, reached at 2:18 p.m. CDT under mostly clear skies with light northerly winds. This value aligns precisely with the market’s dominant 66-67°F bin and sits just 2°F below the 1991-2020 daily normal high of 69°F. The NWS climatological summary provides the authoritative measurement used for resolution, drawing from calibrated instrumentation at the primary station. Trader consensus at near-100% reflects this verified data point with minimal uncertainty; only an unlikely post-publication correction to the official record or a shift in the designated reporting station could alter the outcome.