Beijing’s overnight low on August 22 is shaped by late-summer atmospheric conditions, including the strength of the subtropical high, residual monsoon moisture, and expected thunderstorm activity that limits radiational cooling. Current ensemble guidance from global models shows partly cloudy to overcast skies with light winds and dew points near 20 °C, supporting minimum temperatures clustered around 23–25 °C. Traders have concentrated probability on 23–24 °C because recent model runs have stabilized in that narrow range, with only modest spread from differences in boundary-layer mixing and cloud timing. Clearer or drier conditions could push the low toward 22 °C or below, while persistent cloud cover or evening showers would favor 25 °C or higher; the two-day lead time keeps these scenarios plausible but secondary to the consensus forecast.