Recent National Weather Service and model guidance for Chicago on September 29 points to a daily maximum in the low-to-mid 70s under partly cloudy skies and southerly flow, establishing the 74–77°F range as the market focus. This consensus arises from a building ridge allowing warmer advection after cooler northeasterly conditions earlier in the week, with ensemble spreads typically spanning 70–76°F. Historical late-September climatology for the city shows averages near 72°F, providing context for why traders assign the highest implied probability to 76–77°F while still pricing meaningful odds for 74–75°F. Updated model runs and the next NWS forecast discussion will likely refine the exact peak as the event window narrows.