**Trader sentiment heavily favors low September total precipitation in Seoul (<75 mm at 69.5% implied probability), driven by observed dry conditions through mid-month and ensemble forecasts showing limited additional rainfall.** As of September 10, 2026, early-month accumulations remain modest (roughly 30–40 mm in available station data), well below the long-term September average of 140–160 mm. Recent high-pressure dominance has suppressed convective activity and typhoon influences, with National-level forecasts and models (including ECMWF ensembles) indicating mostly dry or low-probability light rain through at least September 20–24. This pattern aligns with below-normal rainfall scenarios, as steering flows and atmospheric stability limit moisture transport. While late-month variability from changing monsoon remnants or distant systems could add rainfall, current model consensus and the proximity of the month’s midpoint support the market’s strong tilt toward totals remaining under 75 mm. Historical analogs with similar early-September dryness often finish the month drier than average.