Early September observations and short-term forecasts from the Korea Meteorological Administration show mostly dry conditions across Seoul, with high-pressure dominance and limited moisture transport suppressing rainfall totals so far, positioning the <75 mm outcome as the market leader. Historical September averages range from 140–170 mm, driven by the retreating East Asian monsoon and typhoon activity, yet interannual variability remains high depending on storm tracks and the subtropical high’s position. Recent shifts toward an emerging autumn rainy season, linked to warmer sea surface temperatures and altered typhoon patterns, introduce upside risk for higher bins later in the month, though current ensemble guidance indicates minimal near-term accumulation. Traders weigh these factors against resolution thresholds tied to official monthly totals.