Official measurements from the National Weather Service at Chicago O’Hare recorded a daily maximum of 68°F on September 23, 2026, confirming the market-implied outcome. Persistent cloud cover and breezy conditions suppressed daytime heating, producing a high five degrees below the 1991–2020 normal of 73°F while keeping overnight lows elevated near 60°F. This outcome aligns with recent model guidance and surface observations that showed limited solar insolation under a stable post-frontal air mass. Trader consensus at essentially 100% reflects the finality of verified station data used for resolution, though minor adjustments could theoretically arise from quality-control reviews of preliminary climatological reports.