Forecast models and real-time observations from the Korea Meteorological Administration indicate a daily maximum of 28°C in the Incheon-Seoul area on September 22, driven by stable high pressure, light variable winds, and partly cloudy conditions that limit afternoon heating while preventing significant cooling. This aligns with regional climatology for late September, where average highs hover near 25°C but current synoptic patterns support a modest positive anomaly. Trader consensus at 100% implied probability reflects the narrow uncertainty range in short-term numerical weather prediction, with resolution hinging on the official highest recorded temperature at representative stations. Unexpected increases in cloud cover or localized sea-breeze effects could still shift the final value by 1–2°C before sunset.