Traders see near-even odds between 120-130 mm and sub-100 mm totals for Seoul in June 2026 because the East Asian monsoon front's arrival timing remains uncertain. Historical climatology places the June average near 130 mm, with most rainfall concentrated after mid-month as the Jangma front strengthens. Current forecasts from the Korea Meteorological Administration indicate limited precipitation through the first half of June, followed by rising humidity and convective activity in the latter half. Key variables include the precise latitude of the subtropical high, sea-surface temperature anomalies in the western Pacific, and any early typhoon influences that could shift totals by 30-50 mm. Model spread on late-month rainfall keeps the sub-100 mm and near-average bins closely matched.