**Uncertainty in short-range numerical weather prediction models drives the closely matched market odds around 23–27°C for Chongqing’s September 11 maximum.** An approaching cold front and high-pressure shift from the north are expected to end the recent heatwave, with official guidance from the China Meteorological Administration indicating daytime highs falling from the mid-30s°C into the upper 20s or lower on the 11th amid increasing cloud cover and patchy rain. Chongqing’s Yangtze River basin topography can trap moisture and limit daytime heating under overcast skies, while urban heat-island effects and variable wind patterns add local variability. Ensemble spreads in global models reflect this sensitivity to exact timing of the frontal passage and precipitation amounts, producing the balanced probabilities across the 23–27°C outcomes. Updated model runs and official forecasts through September 10–11 will likely refine the range.