Korea in Summer: June, July, August

July alone brings Seoul more rain than the first five months of the year put together, and so does August.

The rainy season has no forecast

Searching for this year’s start date is a waste of an evening. The weather service stopped forecasting the start and end of the rainy season in 2009, and repeated it when the question circulated online in 2026. Its reason is that rainfall has become too variable for a long-range call to hold. Japan and China dropped theirs for the same reason.

What exists instead is the record after the fact. On the 1991 to 2020 normals, the central region that includes Seoul gets its wet spell from around 25 June to around 26 July, roughly a month.

That is a typical year’s shape, not a timetable. If your dates fall inside it, leave a few afternoons free for indoor plans.

Month by month

Thirty years of Seoul records, 1991 to 2020, as published by the Korea Meteorological Administration.

June is the gentlest of the three on every column. Its rainfall is under a third of July’s, and afternoons are nine degrees warmer than nights.

July rains on sixteen days out of thirty-one, with humidity at 76 per cent.

August runs hottest both by day and by night.

Heat warnings since June 2026

On 1 June 2026 the warnings switched from air temperature to perceived temperature, which takes humidity into account. There are now three levels.

A tropical night still means one that stays above 25°C. What is new is a tropical night advisory. It can be issued only in areas already under a heat advisory. The threshold there is 25°C at night, raised to 26°C in cities of over half a million people and 27°C on Jeju.

Guides written before 2026 quote the old air temperature thresholds. Live warnings, and typhoon tracks, are on the weather service’s site.

Korea also opens designated cooling shelters from 15 May to 30 September, around ninety-three thousand of them in community centres, libraries, banks, shops and shopping centres. Eligibility has been widened from elderly residents to the general public. Official notices say nothing either way about visitors, and each site is listed as open to anyone or restricted, so look up a specific one on the national disaster portal before walking in.

Palace nights take a break

Gyeongbokgung does not open after dark in high summer. The palace’s booking page gave the 2026 spring season as 13 May to 14 June, and a notice for the autumn season had it reopening on 2 September. The daytime special viewing of the Gyeonghoeru and Hyangwonjeong pavilions stops too, and its notice lists “the hot season, June to August” among the periods it does not run.

So a night at the palace is possible in June up to the middle of the month, and not in July or August. Those dates are for Gyeongbokgung only.

The city runs outdoor pools along the Han river instead, roughly mid-June to the end of August. Seoul announces the dates each May or June.

Typhoons

Typhoons affecting the Korean peninsula average 0.3 in June, 1.0 in July and 1.2 in August on the same normals. August is the peak of those three and sits above September’s 0.8, the month most people associate with typhoons.

No operator publishes a standing policy on what a typhoon does to flights or trains.

Long evenings

Sunset on the longest day comes two hours and forty minutes later than on the shortest day in December. In June and July the sun sets just before eight, so an evening out after the afternoon heat still has daylight.

Public holidays, summer 2027

Memorial Day is Sunday 6 June, with no substitute day off.

Constitution Day is Saturday 17 July, with Monday 19 July as the substitute. It became a public holiday again in 2026 after eighteen years, so older guides leave it out.

Liberation Day is Sunday 15 August, with Monday 16 August as the substitute.