Incoming cold air is the dominant driver of trader sentiment for Chongqing’s September 10 minimum temperature, with official forecasts showing a sharp drop from recent highs near 38 °C as a frontal system arrives overnight September 9. Meteorological guidance from local agencies projects lows of 18–19 °C under increased cloud cover and scattered rain, consistent with historical September climatology of roughly 22 °C average minima but cooler than the preceding heat wave. Model consensus supports this cooling trajectory, though small differences in frontal timing and boundary-layer mixing create genuine uncertainty around the precise threshold between 19 °C or below and the mid-20 °C range. The near-even split between the ≤19 °C and ≥29 °C outcomes reflects traders weighting the risk of forecast revisions against the strong signal for rapid temperature advection. Updated model runs and surface observations over the next 48 hours will likely resolve much of the spread.