Recent National Weather Service forecasts for Chicago indicate a mild overnight low in the low to mid-60s Fahrenheit on September 29 under mostly cloudy skies and southerly flow, supporting trader emphasis on the 64°F-or-higher outcome at 41.5% implied probability. Model consensus reflects limited radiative cooling from persistent cloud cover and light winds, though slight variations in timing of any clearing or moisture could push readings into the 52–55°F range favored by the next cluster of probabilities near 39%. These closely matched odds capture genuine short-term forecast spread typical 24 hours ahead, with official observations and updated model runs expected to resolve the market quickly.