**Forecast model spreads and subtle variations in overnight radiative cooling are keeping trader odds tightly clustered around 15–18°C for Zhengzhou’s September 26 minimum.** Official guidance from sources such as the GFS and regional models shows projected lows near 18–21°C under partly cloudy skies and light southerly winds, yet small differences in cloud cover, boundary-layer moisture, and wind speed can shift the realized minimum by 2–3°C. With the market resolving in under 24 hours, any late model run that increases clear-sky potential or reduces mixing would favor the lower bins, while persistent cloudiness would support the 17–18°C outcomes. Historical September minima near 16°C provide context, but current synoptic conditions and ensemble spread explain why no single outcome exceeds 50% implied probability.