Typhoon Risk in Korea by Month: 3.4 a Year, 0.1 in October
The Korea Meteorological Administration's typhoon statistics page puts the 1991 to 2020 average at 25.1 storms forming in the western North Pacific in a year, of which 3.4 affect Korea. Broken out by month, the share that affects Korea runs 0.3 in June, 1.0 in July, 1.2 in August, 0.8 in September, and 0.1 in October.
That October figure is the one worth carrying into a booking decision. It is also less reassuring than it first looks, because of what the agency means by "affect."
What the KMA counts as affecting Korea
Since 2011 the test has been a narrow one. A storm counts if a typhoon advisory took effect inside a Korean warning zone, and nothing about landfall or rainfall enters into it. The wording sits in a KMA press release issued at 03:00 on June 2, 2026: "한반도 영향 태풍은 2011년부터 우리나라 특보구역 내의 태풍특보 발효 유무로 결정" (an affecting typhoon is determined by whether a typhoon advisory is in force within our warning zones).
That same release shows how loose the test can be. The trigger was Typhoon No. 6, Jangmi, and the zone was 남해동부바깥먼바다, the outer far sea off the eastern half of the south coast. Open water. On that basis Jangmi went into the record as the third-earliest affecting typhoon since 1951, behind Betty on May 28, 1961 and Linfa on May 30, 2003.
Hold onto that when you read a year's total. The count is a count of advisories, and one advisory can sit over water no visitor goes near.
Month by month, on the 30-year average
| Month | Storms formed (avg) | Affecting Korea (avg) |
|---|---|---|
| June | 1.7 | 0.3 |
| July | 3.7 | 1.0 |
| August | 5.6 | 1.2 |
| September | 5.1 | 0.8 |
| October | 3.5 | 0.1 |
Figures from the KMA's typhoon occurrence statistics, climate normals for 1991 to 2020.
Look at the last two rows together. Storm formation drops by about a third between September and October, 5.1 down to 3.5, while the count reaching Korean warning zones falls eightfold. If your dates can move a fortnight, that is the fortnight to move. The page offers no explanation for the gap, just the two figures, 0.8 and 0.1.
August is the peak on both columns. An average of 1.2 storms reaching a Korean warning zone, against 5.6 forming somewhere in the basin that month.
The monsoon is roughly a month, and it slides around
Jangma gets described in English travel writing as "the rainy season," which suggests a whole summer. The KMA's monsoon normals table draws a narrower window, three regional rows averaged over 1991 to 2020.
- Central Korea (Seoul included): June 25 to July 26, 31.5 days, 17.7 days with rain, 378.3mm
- Southern Korea: June 23 to July 24, 31.4 days, 17.0 rain days, 341.1mm
- Jeju: June 19 to July 20, 32.4 days, 17.5 rain days, 348.7mm
Seventeen or eighteen wet days inside a thirty-one day stretch. Thirteen to fifteen days in each window record no rain at all, and the central row, the one Seoul sits in, is the wettest of the three at 378.3mm.
The window also shifts year to year, and 2026 shifted late. News1, reporting the KMA's end-of-season announcement on July 27, gave this year's dates as June 30 to July 19 on Jeju (20 days), June 30 to July 25 in the south (26 days), and July 1 to July 26 in the centre (26 days). Measured since records began in 1973, that was the 6th shortest jangma on Jeju, the 10th shortest in the south, and the 12th shortest in central Korea.
Short did not mean uniformly wet or uniformly dry. The KMA's July climate summary, reported by Kyunghyang Shinmun on August 5, put national rainfall for the month at 220.0mm, or 74.2% of normal, across 13 rain days. South Gyeongsang province got 68.0mm against a normal of 304.7mm, 22.3%, the lowest July on record there. The national mean temperature ran 2.2 degrees above normal, the third-hottest July after 1994 and 2025.
If you were travelling in the southeast in July hoping the monsoon would break the heat, it did not.
Where 2026 has landed so far
As of today, September 17, the KMA's typhoon occurrence table shows 25 storms formed this year and one counted as affecting Korea. That one is Jangmi, on June 2, with its advisory over open sea.
Number 25, Dujuan, is live right now. The KMA's English typhoon page listed it at 16:00 KST today, with forecast positions running out toward waters east of Tokyo through September 22. Wikitree, in a piece published at 14:14 today, quotes KMA forecast analyst Gong Sang-min saying "진로가 다소 바뀔 수는 있지만 우리나라로 오기는 어려울 것" (the track may shift somewhat, but it will be hard for it to come to us).
One advisory in a year of 25 storms sits well under the 3.4 average, with October and November still on the board.
What to open yourself
The KMA's English typhoon information page carries the live track, the forecast positions with central pressure and wind speed, and the issue time in KST. Bookmark that one as soon as you have dates. For the table above, the Korean-language occurrence statistics page prints each year's total with the count affecting Korea in parentheses beside it, readable through any browser translation.
For alerts once you land, install the Ministry of the Interior and Safety's Emergency Ready App before you fly and set your language when you open it. It carries disaster information in 22 languages including English, per Seoul's own English city page.
Now the honest limit, because this is where a lot of weather posts trail off. A 30-year monthly average answers which month and nothing finer. The KMA's own track forecast for Dujuan today ran five days out, to September 22, so nothing open to you can say whether your Thursday in Busan gets rained on six weeks from now. The ranking of months is real; the week-level answer does not exist, in Korean or in English.
If a Korean trip of yours ran into one of these, which month was it, and did it change anything you had planned?
This is a running news series, not a one-off post — new stories go up twice a day, roughly 7am and 7pm Korea time.
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