Clear skies under a high-pressure system over central China, combined with northerly winds, have driven Seoul and Incheon daytime highs to 21°C on October 6, 2026, aligning with National Weather Service-equivalent forecasts and morning observations around 13–15°C that rose steadily under dry conditions. This positions the 21°C outcome at 99.1% implied probability, reflecting trader consensus on official maximum temperature readings from Incheon stations. Recent cold wave alerts and radiative cooling overnight reinforced the moderate peak, consistent with climatological October baselines near 19–21°C. A realistic challenge would require sustained warmer advection or localized measurement anomalies pushing the official high to 22°C or above before resolution.