**Trader consensus at 100% for a 22°C daily maximum in the Seoul-Incheon region on September 10 stems from official meteorological observations and short-range model guidance confirming that peak temperature.** Clear to partly cloudy skies, light northeasterly winds, and modest insolation under post-summer conditions produced a measured high near this value at representative stations such as Incheon International Airport. Korea Meteorological Administration surface data and hourly reports show afternoon readings stabilizing around 22–25°C before cooling, aligning with the market-implied outcome. Realistic challenges include final quality-controlled revisions to the official daily maximum, differences between airport and urban Seoul stations, or late-day measurement adjustments exceeding 1°C. No significant warm-air advection or model bias appears in the latest guidance to alter this outcome.