Recent National Weather Service and model guidance indicate a cold front will sweep across the Chicago area on October 1, bringing heavy rain and shifting winds to the north. This sets up post-frontal cooling for October 2, with forecast highs centered in the lower 60s under partly cloudy skies as drier, cooler air arrives. Historical averages near 69–70 °F provide context, yet current steering patterns and northerly flow favor readings below the seasonal norm. Trader consensus, reflected in the 51.5 % implied probability on 64–65 °F, incorporates remaining model spread and the narrow window for any warmer bias before resolution, while lower bins capture downside risk from stronger cooling. Updated NWS briefings and morning observations will refine the final range.