Traders see nearly equal implied probabilities for a Zhengzhou low of 15°C or below versus 25°C or higher on September 18 because current ensemble forecasts from regional models show substantial spread around the historical mid-September average overnight minimum near 17°C. Key differentiating factors include the strength of southerly flow versus any incoming northerly surge that could enhance radiational cooling under clearer skies, along with boundary-layer moisture levels that influence dew-point depression and minimum temperatures. With the date only hours away, the next model runs and observational updates from surface stations will likely narrow the range, as small shifts in cloud cover or wind speed can easily move the outcome across the closely contested thresholds.