Recent influx of cold air from a northern continental high-pressure system has driven sharp overnight cooling across the Seoul-Incheon region ahead of October 2, with clear skies and northwest winds expected to enhance radiative cooling and lower minimums. Korea Meteorological Administration guidance and ensemble models indicate Incheon lows near 11–14°C under sunny conditions, consistent with the market’s leading implied probabilities for 13°C (42.5%) and 14°C (31.5%). Trader positioning reflects model agreement on this range while acknowledging typical 1–2°C variability from exact observation site, wind shifts, or boundary-layer details. Updated forecasts through October 1 will refine these probabilities before resolution.