Cold air advection associated with a strengthening northeasterly flow is the dominant driver behind current market-implied odds for Jinan’s September 9 high temperature. Official guidance and ensemble forecasts indicate a notable drop from recent 30–32 °C readings, with most models converging on a daytime maximum near 23–25 °C under increasing cloud cover and 3–4 m s⁻¹ winds. Uncertainties in frontal timing and boundary-layer mixing produce the wide probability distribution, particularly the 30.5 % chance attached to 26 °C or higher. Traders are weighting the latest China Meteorological Administration and global model runs that emphasize modest daytime heating limited by the cool air mass, while noting that any delay in the frontal passage could allow brief warming above 25 °C before resolution.