The near-even split between 21°C and 22°C reflects converging short-range forecast models showing a daytime maximum in that narrow band for Incheon on October 1, driven by northwesterly flow advecting cooler air behind a recent frontal passage and moderate insolation under partly cloudy skies. Seasonal climatology places early-October highs near 22°C, but model consensus on boundary-layer mixing and limited cloud cover creates tight uncertainty around exact peak values. Traders weigh minor differences in predicted wind speeds and radiative heating against historical analogs, with resolution hinging on official Korea Meteorological Administration observations at the Incheon station.