**Recent forecast updates from official and ensemble models show a frontal system bringing widespread cloud cover, high humidity, and periods of rain to the Seoul-Incheon area on August 31, which is the dominant factor capping daytime heating.** This setup favors a maximum temperature clustered around 24–26°C rather than the seasonal late-August average near 29–30°C. Multiple sources, including PredictWind, WeatherBug, Met Office, and Korean Meteorological Administration guidance, point to highs of 25–26°C under mostly cloudy skies with 40–60% rain chances and light northeast winds, while some runs allow brief afternoon breaks that could reach 27–28°C. The narrow spread between the leading 25°C (22%) and 27°C (21.5%) market outcomes reflects model uncertainty in exactly how much solar radiation penetrates the cloud deck and how quickly any showers develop—small differences in timing or intensity of precipitation can shift the daily maximum by 1–2°C. Traders are weighting the higher probability of sustained overcast conditions and evaporative cooling from rain, which historically suppresses peaks in similar synoptic patterns, while still acknowledging the possibility of partial clearing that would push readings into the upper 20s. Updated model runs and next-day observational trends will be the key near-term catalysts.