Market-implied odds strongly favor a 23°C high in Seoul/Incheon on October 4, driven by consensus numerical weather models showing afternoon peaks near that level under partly cloudy skies before an approaching frontal system brings rain and modest cooling by evening. Recent observations confirm daytime maxima reached 23°C on October 3 amid autumnal variability, with overnight lows in the mid-teens supporting similar recovery before precipitation arrives late on the 4th. This positions 22–24°C as the dominant range while lower or higher thresholds remain unlikely given stable steering patterns and limited model spread. Updated KMA guidance and afternoon observations will refine resolution.