Official National Weather Service observations from Chicago O’Hare and Midway stations recorded a daily maximum of 82°F on August 22, 2026, under clear skies with light northwest winds and dew points in the mid-50s that limited afternoon humidity. This value aligns closely with the market’s dominant 80–81°F outcome, reflecting the precise bin used for resolution and the near-certainty expressed by traders once preliminary climate reports were released. Historical normals for the date average 82°F, and recent model guidance had correctly anticipated modest warmth without the heat or moisture needed for higher readings. A last-minute station adjustment or revised quality-control flag remains the only plausible development that could shift the final classified high outside the leading bin.