**Recent model consensus and official guidance from the Korea Meteorological Administration (KMA) and international sources place the expected daily maximum for Incheon/Seoul on August 24 in the narrow 30–32 °C range, which is why the 30 °C and 31 °C outcomes dominate trader positioning at combined ~66 % implied probability.** Persistent influence of the North Pacific high-pressure ridge is the dominant driver, advecting warm, moist southerly flow across the region after scattered showers cleared central areas on August 22. This setup favors strong daytime insolation under partly cloudy skies, with forecast highs clustered near 31 °C at Incheon International Airport and similar values for Seoul proper. Ensemble and deterministic runs show only modest spread because the ridge axis remains stable and steering flow is light-to-moderate from the southwest. Small differences among the leading bins arise from microphysical and boundary-layer details: slightly greater cloud cover or residual low-level moisture from lingering instability could shave 1 °C off peak values (favoring 30 °C), while clearer skies and stronger mixing would allow brief excursions to 32 °C. Precipitation probability remains low (10–40 % depending on the model), so widespread cooling from rain is unlikely. Historical late-August climatology for the area supports maxima of 30–32 °C as the most probable outcome under similar large-scale patterns. Traders are therefore pricing the tight clustering around the model mean while assigning low weight to outliers, reflecting both the short forecast horizon (now <48 hours) and the limited room for large deviations given the established ridge. Updated KMA and global model runs on August 23 will be the next key inputs likely to refine these probabilities before resolution.