Persistent rain and extensive cloud cover from an autumn weather system have suppressed daytime heating across Chongqing, limiting the September 17 maximum to the low 20s °C range according to official observations and model consensus. Cool northeasterly flow and high humidity (near 90%) further reduced solar insolation and evaporative cooling effects, keeping temperatures well below the seasonal climatological average of 27–30 °C. Real-time station data showing peaks near 22 °C or lower underpin the market’s near-certain pricing on 21 °C or below. Only an unexpected late-day clearing or measurement revision at the primary reporting station could realistically alter the outcome before final verification.