Traders see near-even odds across 300–400 mm totals for Seoul in August 2026 because roughly one-quarter of the month has passed with limited accumulation so far, leaving the outcome highly sensitive to remaining convective activity and any late-season typhoon tracks. The East Asian summer monsoon typically produces short, intense downpours through early August, while the subsequent retreat allows greater variability driven by steering patterns, sea-surface temperatures, and upper-level dynamics that can either suppress or enhance rainfall. Historical August averages near 250–350 mm provide a baseline, yet interannual swings from tropical cyclone frequency and monsoon timing keep mid-range bins clustered at 45 % implied probability. Updated Korea Meteorological Administration medium-range outlooks and ensemble precipitation forecasts will be the next key inputs as the month progresses.