Persistent cloud cover and rainfall from an active regional weather pattern are capping solar heating and keeping Chongqing's September 17 maximum temperature tightly clustered around 21–24°C in official forecasts. Light easterly to northerly winds, high humidity near 90 percent, and widespread precipitation—consistent with China Meteorological Administration guidance for moderate to heavy rain—suppress daytime warming well below the late-September climatological average of roughly 27°C. Ensemble model spreads remain modest, with minor differences in cloud breaks or rain timing the main variables that could push the observed high one degree higher or lower at the primary reporting station. Market odds reflect this narrow uncertainty range ahead of final verification.