**Trader consensus has converged on a 20°C high for Seoul/Incheon on October 5, 2026, reflecting official forecasts and real-time observations.** Korean Meteorological Administration guidance and multiple models, including those cited by Yonhap and Met Office summaries, projected a daytime maximum of 20°C under partly cloudy skies with northwesterly winds. Actual readings through the afternoon peaked near this level, consistent with a sharp cooldown from the prior day’s 23°C high driven by northerly cold-air advection. Incheon station data, the typical resolution benchmark, aligned closely with this value. Realistic challenges include minor station-to-station variance or a late surge pushing the official maximum to 21°C, though current observations and model consensus make such shifts unlikely before resolution.