**Latest National Weather Service forecasts and short-range model guidance position a mid-60s high as the most probable outcome for Chicago on October 2.** A cold front is expected to sweep through on October 1, delivering widespread rain and a daytime peak near 70–71°F before northerly winds strengthen behind the boundary. This shift favors clearing skies and cooler advection on Friday, with highs most often projected between 61°F and 65°F across guidance, though some ensemble members allow brief afternoon warming into the upper 60s if clouds clear earlier than anticipated. The market’s heavy weighting toward 66–67°F (46.5%) reflects residual uncertainty in timing and boundary-layer mixing, while lower-probability bins above 68°F capture outlier warmer scenarios. Historical October 2 normals near 69–70°F underscore how this post-frontal regime deviates from climatology. Updated NWS point forecasts and afternoon model runs will provide the next key data points before resolution.