Trader consensus reflects substantial uncertainty around Seoul’s typical June rainfall of 130–145 mm, with the market’s closely bunched probabilities driven primarily by variable monsoon onset timing. Early June has featured only scattered showers under building humidity, consistent with climatological patterns where the East Asian summer monsoon usually intensifies after mid-month and supplies the bulk of seasonal totals via frontal systems and convective bursts. Official Korea Meteorological Administration outlooks and ensemble model spreads highlight divergent scenarios for late-June precipitation intensity, directly affecting whether monthly accumulation stays below 110 mm or exceeds 150 mm. Key resolution hinges on updated medium-range forecasts and observed rainfall through June 30.