Current forecasts from multiple models indicate Shanghai's overnight low on September 25, 2026, will likely fall between 23–25°C, aligning with the market's tight clustering around those outcomes. Late-September seasonal norms feature declining solar insolation and average lows near 22°C, but persistent southerly flow and moderate humidity are limiting radiative cooling overnight. Incoming cloud cover and light rain signals for the period could further moderate the minimum by trapping heat, while clearer intervals might allow a dip toward 23°C. Traders appear to weigh these subtle differences in expected nocturnal conditions and model consensus on boundary-layer moisture, with resolution hinging on the final observed reading from official stations. Updated runs from the China Meteorological Administration will refine guidance ahead of the date.