**Trader sentiment for the highest temperature in Seoul (Incheon) on August 15 centers on the narrow gap between 30°C and 31°C outcomes because official and ensemble forecasts diverge on whether daytime heating will reach the upper 20s or low 30s amid variable cloud cover and scattered showers.** The Korea Meteorological Administration (KMA) short-range guidance currently projects a 32°C maximum under mostly cloudy skies with a 30% precipitation chance, while other models such as the UK Met Office favor a 30°C ceiling. These differences arise from uncertainty in how much solar insolation will be reduced by lingering moisture and weak frontal activity following the early-August heatwave peak. High humidity typical of mid-August in the region supports elevated heat indices, yet increased cloudiness and any convective development can suppress surface temperatures by limiting afternoon warming. With the observation window only two days away, updates to model runs and official briefings on steering patterns and moisture transport remain the key near-term catalysts that could shift the market-implied distribution between these closely matched outcomes.