Recent trader positioning around Seoul’s June 2026 rainfall reflects uncertainty in the precise onset and strength of the East Asian summer monsoon, which typically begins shifting moisture northward in the latter half of the month. With roughly 60-70 mm likely accumulated through mid-June under relatively stable early-summer conditions, outcomes hinge on whether late-month frontal systems and southerly flow deliver near-normal totals near 130 mm or trigger heavier episodes exceeding 160 mm. Korea Meteorological Administration guidance notes potential above-average precipitation tied to enhanced moisture transport, yet model consensus on exact timing and intensity remains divided, sustaining the tight spread across 110-160 mm brackets.