Trader consensus on a 21°C high for Seoul/Incheon on October 3 reflects consistent model guidance and real-time observations from sources including the Korea Meteorological Administration and GFS runs. Afternoon temperatures have peaked near 21–22°C under mostly cloudy skies with light southeast winds and moderate humidity, aligning with early-October climatology for the region where daily maxima typically range 20–23°C. Official station data through the afternoon have not exceeded this threshold, supporting the market-implied certainty. A shift to clearer conditions or localized warming could push readings higher, while measurement timing or site-specific reporting differences remain the primary variables that might alter the recorded maximum before resolution.