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Almost three quarters of Seoul’s rain falls in four months, June to September. For cherry blossoms, aim for early April. For autumn leaves, late October. For mild weather without either, October first and May second. The table shows why, and each season has its own guide, linked at the end.

Seoul’s year

Korea Meteorological Administration normals, 1991 to 2020.

Average high Average low Rainfall Wet days
January 2.1°C / 36°F -5.5°C / 22°F 16.8mm 6.1
February 5.1°C / 41°F -3.2°C / 26°F 28.2mm 5.8
March 11.0°C / 52°F 1.9°C / 35°F 36.9mm 7.0
April 17.9°C / 64°F 8.0°C / 46°F 72.9mm 8.4
May 23.5°C / 74°F 13.5°C / 56°F 103.6mm 8.6
June 27.6°C / 82°F 18.7°C / 66°F 129.5mm 9.9
July 29.0°C / 84°F 22.3°C / 72°F 414.4mm 16.3
August 30.0°C / 86°F 22.9°C / 73°F 348.2mm 14.7
September 26.2°C / 79°F 17.7°C / 64°F 141.5mm 9.1
October 20.2°C / 68°F 10.6°C / 51°F 52.2mm 6.1
November 11.9°C / 53°F 3.5°C / 38°F 51.1mm 8.8
December 4.2°C / 40°F -3.4°C / 26°F 22.6mm 7.8

Patterns in the table

July and August alone take more than half of the year’s rain. Outside the four wet months, May’s 103.6mm is the highest.

January has both the lowest temperatures and the lowest rainfall. February has the fewest wet days. August is hottest by day and by night. July is wettest by both rainfall and wet days, with rain on more than half of them.

October and May sit where warmth meets dryness. October’s average high is about twenty degrees with rain on around six days. May is a few degrees warmer and has twice the rainfall.

Dates that decide the month

Cherry blossoms. Seoul’s official flowering date on the normals is 8 April. In 2026 it came on 29 March, ten days early, and three days before the one private forecast that gave a flowering date.

Autumn leaves. The 2026 national forecast put the peak in late October, starting in the northern mountains early in the month and reaching the south in early November.

Palace nights. Gyeongbokgung’s night viewing comes in seasonal blocks. In 2026, spring ran 13 May to 14 June and autumn 2 September to 2 October, with no night entry in between. The blossoms finish before the spring block starts.

The rainy season. No one forecasts it, the weather service included. On the normals, the central region around Seoul is wettest from about 25 June to about 26 July.

Fine dust. The government’s management season runs December to March, when particle levels are highest. March is the only spring month inside it.

Season guides