The official National Weather Service climate summary for Chicago O’Hare recorded a maximum temperature of 70 °F on October 1, 2026, reached at 2:24 p.m. CDT, aligning precisely with the market’s 100 % consensus on the 70–71 °F bin. This outcome reflects verified observational data from the primary reporting station rather than forecasts or models. Near-normal early-October conditions, with a daily average high around 69–70 °F, supported the result amid light rain and overcast skies that limited further warming. A realistic challenge would require a revised official reading from the NWS or a different primary station exceeding 71 °F, though such adjustments are rare once the daily climate report is issued.