Forecasts from multiple models indicate minimum temperatures in Beijing on September 3 around 19–21°C under mostly clear skies and light variable winds, supporting radiative cooling overnight but limited by residual summer warmth and urban heat effects. Trader sentiment clusters around mid-teens to low-20s outcomes because ensemble spreads in global and regional models show modest uncertainty from potential changes in cloud cover or wind speed, which can alter the rate of nocturnal temperature drop by 2–4°C. Historical September climatology places average lows near 19°C, providing a baseline, while the absence of incoming cold fronts or significant moisture keeps probabilities balanced rather than skewed toward extremes. Updated model runs and official observations from the China Meteorological Administration over the next 48 hours will likely narrow the range.