Forecast uncertainty in short-term numerical weather prediction models for cloud cover, humidity, and thunderstorm activity on August 22–23 primarily drives the tight clustering of Polymarket odds around 22–26°C for Beijing’s daily minimum. In the city’s humid subtropical monsoon regime, nighttime radiative cooling is highly sensitive to these variables: clear skies and lower dew points enable greater heat loss toward the surface, potentially pushing lows toward 22–23°C, while persistent cloudiness or rain from upstream systems limits cooling and supports 24–25°C readings. Recent model runs show mixed signals on precipitation timing, keeping trader consensus balanced across these thresholds rather than favoring extremes. Official guidance from agencies like the China Meteorological Administration will refine these projections ahead of resolution.