Recent numerical weather prediction models indicate substantial uncertainty in Jinan’s overnight minimum on September 5, with clear skies and light northeasterly winds promoting strong radiative cooling after sunset. Ensemble spreads from sources such as ECMWF and CMA place the lowest temperature between roughly 17–21 °C, producing the tight clustering of market-implied probabilities around the 15–22 °C thresholds. Historical September climatology shows typical lows near 19 °C, but day-to-day variability in boundary-layer moisture and wind speed can shift the realized minimum by several degrees. Updated high-resolution model runs and official CMA guidance expected overnight will likely narrow the range before markets close.