Recent National Weather Service forecasts for Chicago highlight a moderating air mass and weak high-pressure ridge building in from the south, supporting trader consensus around the 62°F-or-higher bin at 40% implied probability. Ensemble guidance from NOAA’s Global Forecast System and European Centre models shows overnight lows potentially holding in the mid-50s to low-60s through October 8, with limited cold advection expected. Historical October climatology places typical daily lows near 48–52°F, yet current 500-hPa heights and dew-point trends favor above-normal readings. Key uncertainties remain in the precise timing of any weak frontal passage or cloud-cover changes that could drop minima into the 50–53°F range, reflected in the cluster of 34–35% outcomes for those bins. Updated model runs and local observations over the next 48 hours will likely refine these probabilities before market resolution.