**Trader consensus at 100% for a 27°C high in Seoul/Incheon on September 8 reflects official observations from the Incheon International Airport station confirming that peak temperature under clear skies and light northeasterly winds.** Forecast models, including GFS runs, aligned closely with a daytime maximum near 27–29°C, and late-day readings settled precisely at the 27°C threshold used for market resolution. This outcome aligns with climatological norms for early September, when average highs reach about 25–26°C, and recent dry, stable atmospheric conditions suppressed further warming. The near-certain positioning leaves little room for revision unless post-hoc quality control or alternative station data alters the official maximum, though such adjustments remain rare for this well-monitored site.