**Forecast models for Jinan on September 15, 2026, point to an overnight low near 19–22°C under mostly clear skies and light southwesterly flow.** This setup favors moderate radiative cooling after daytime highs in the low 30s°C, with dew points around 15–18°C limiting further drops. The near-even market odds between 12°C or below and 22°C or higher reflect model spread in boundary-layer mixing and exact cloud timing, as stronger winds or thin high clouds could suppress cooling while calm, dry conditions enhance it. Historical September climatology shows typical lows near 17–19°C, so the tight spread captures genuine uncertainty in the final 24–48 hours of guidance from agencies like the China Meteorological Administration. Traders are watching the next model runs and local station observations for resolution thresholds.