Official Korea Meteorological Administration guidance projects a 25°C minimum for Seoul-Incheon on August 21 amid cloudy skies, 30–60% rain chances, and light winds that curb nocturnal radiative cooling. High humidity and limited clear-sky intervals keep overnight lows near the late-summer climatological average of roughly 22–24°C, positioning 24°C and 25°C as the dominant outcomes in trader consensus. Recent short-range model runs show modest spread tied to the timing of any showers, which could allow slightly greater cooling if skies briefly clear. This uncertainty, combined with ensemble consistency around the official minimum, underpins the market’s tight clustering at 24–25°C while assigning low probability to extremes outside 23–26°C.