The arrival of a cooler air mass from the north, combined with widespread rainfall, has driven the market's near-certain consensus on a 21°C daily high in Wuhan for September 17. Official forecasts from the Wuhan Meteorological Observatory and regional models consistently project maximum temperatures of 20–22°C under overcast, rainy conditions, with surface cooling from evaporative effects and reduced solar heating. This represents a sharp 8–10°C drop from prior days' readings near 30–32°C. Trader positioning reflects alignment with these verified model runs and observational trends rather than historical September averages around 28–30°C. Late-day clearing or localized model underestimation of insolation remain the only realistic paths to a higher outcome.