Forecast models from sources including the China Meteorological Administration and international ensembles indicate a low near 20–21°C for Chengdu on September 28 amid persistent cloud cover, light rain transitioning to overcast skies, and weak northeasterly winds that limit nocturnal radiative cooling. These conditions reduce the typical diurnal range, supporting trader consensus near the middle of the distribution, yet the near-even split between 17°C-or-below and 27°C-or-higher outcomes reflects lingering model spread in boundary-layer moisture and any late-day clearing that could allow greater overnight temperature drops or retained warmth. Historical late-September baselines for the Sichuan Basin show similar variability under transitional monsoon influences, with official station measurements resolving the exact minimum by local midnight.