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When is Japan's rainy season?

By Gallivanting GadaboutBuilt from official dataSource: Japan Meteorological Agency, checked 5 Oct 2026Contains affiliate links
TL;DR

In the Japan Meteorological Agency's 1991–2020 averages, the rainy season (tsuyu) starts around 10 May in Okinawa and ends around 21 June; in Kanto-Koshin it runs from around 7 June to around 19 July, and in Northern Tohoku from around 15 June to around 28 July.41215 Hokkaido has no rainy season in the agency's announcements.1

Purple hydrangeas in full bloom, Kawasaki, Japan
Purple hydrangeas in full bloom, Kawasaki, Japan. Photo by Keijiro Takahashi on Pexels.

When does the rainy season normally start and end?

The agency announces the rainy season for 12 regions of Japan, leaving out Hokkaido, which has no rainy season.1 Its normal dates are the average for 1991–2020, leaving out years in which no start or end could be identified.4

Normal start and end of the rainy season, 1991–2020, by region (Japan Meteorological Agency)
RegionNormal startNormal end
Okinawa 沖縄around 10 May4around 21 June4
Amami 奄美around 12 May5around 29 June5
Southern Kyushu 九州南部around 30 May6around 15 July6
Northern Kyushu (including Yamaguchi) 九州北部around 4 June7around 19 July7
Shikoku 四国around 5 June8around 17 July8
Chugoku 中国around 6 June9around 19 July9
Kinki 近畿around 6 June10around 19 July10
Tokai 東海around 6 June11around 19 July11
Kanto-Koshin 関東甲信around 7 June12around 19 July12
Hokuriku 北陸around 11 June13around 23 July13
Southern Tohoku 東北南部around 12 June14around 24 July14
Northern Tohoku 東北北部around 15 June15around 28 July15

The agency says the start and the end each take about five days on average to change over, and its dates give roughly the middle of that change.2 That is why each date reads “around”.

Which prefectures are in each region?

  • Northern Tohoku: Aomori, Akita and Iwate.3
  • Southern Tohoku: Yamagata, Miyagi and Fukushima.3
  • Tokai: Aichi, Gifu, Mie and Shizuoka.3
  • Northern Kyushu (including Yamaguchi): Yamaguchi, Fukuoka, Oita, Saga, Nagasaki and Kumamoto.3
  • Southern Kyushu: Miyazaki and Kagoshima (the Satsuma and Osumi areas, Tanegashima and Yakushima).3
  • Amami: Amami city, Oshima district and Toshima village.3

For the other regions, see the agency's list of region names, linked in the sources.3

What these dates cannot tell you

They are averages for 1991–2020, not a forecast: the actual start and end move from year to year, and the agency publishes each year's dates on the pages cited below.2

What this page cannot tell you

  • Averages, not forecasts. Any one year can start or end earlier or later than these dates.
  • Region names are our translation; the Japanese names are the agency's.

Related: When is typhoon season in Japan? · Tokyo weather by month · When do cherry blossoms open in Japan?.

Key takeaways

  • Okinawa's rainy season normally runs from around 10 May to around 21 June.
  • Kanto-Koshin's normally runs from around 7 June to around 19 July.
  • Hokkaido has no rainy season in the agency's announcements.
  • What we would skip: booking around one exact date: the start and end move from year to year.

Sources

Every date comes from the Japan Meteorological Agency's own pages, saved on 5 October 2026. See how we research.

  1. Japan Meteorological Agency, よくある質問（梅雨）. Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.jma.go.jp/jma/kishou/know/faq/faq33.html）
  2. Japan Meteorological Agency, 梅雨入りと梅雨明け（速報値）. Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.data.jma.go.jp/cpd/baiu/index.html）
  3. Japan Meteorological Agency, 予報用語：地域名. Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.jma.go.jp/jma/kishou/know/yougo_hp/tiikimei.html）
  4. Japan Meteorological Agency, 過去の梅雨入りと梅雨明け（沖縄）, 平年 (1991–2020). Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.data.jma.go.jp/cpd/baiu/kako_baiu01.html）
  5. Japan Meteorological Agency, 過去の梅雨入りと梅雨明け（奄美）, 平年 (1991–2020). Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.data.jma.go.jp/cpd/baiu/kako_baiu02.html）
  6. Japan Meteorological Agency, 過去の梅雨入りと梅雨明け（九州南部）, 平年 (1991–2020). Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.data.jma.go.jp/cpd/baiu/kako_baiu03.html）
  7. Japan Meteorological Agency, 過去の梅雨入りと梅雨明け（九州北部）, 平年 (1991–2020). Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.data.jma.go.jp/cpd/baiu/kako_baiu04.html）
  8. Japan Meteorological Agency, 過去の梅雨入りと梅雨明け（四国）, 平年 (1991–2020). Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.data.jma.go.jp/cpd/baiu/kako_baiu05.html）
  9. Japan Meteorological Agency, 過去の梅雨入りと梅雨明け（中国）, 平年 (1991–2020). Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.data.jma.go.jp/cpd/baiu/kako_baiu06.html）
  10. Japan Meteorological Agency, 過去の梅雨入りと梅雨明け（近畿）, 平年 (1991–2020). Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.data.jma.go.jp/cpd/baiu/kako_baiu07.html）
  11. Japan Meteorological Agency, 過去の梅雨入りと梅雨明け（東海）, 平年 (1991–2020). Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.data.jma.go.jp/cpd/baiu/kako_baiu08.html）
  12. Japan Meteorological Agency, 過去の梅雨入りと梅雨明け（関東甲信）, 平年 (1991–2020). Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.data.jma.go.jp/cpd/baiu/kako_baiu09.html）
  13. Japan Meteorological Agency, 過去の梅雨入りと梅雨明け（北陸）, 平年 (1991–2020). Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.data.jma.go.jp/cpd/baiu/kako_baiu10.html）
  14. Japan Meteorological Agency, 過去の梅雨入りと梅雨明け（東北南部）, 平年 (1991–2020). Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.data.jma.go.jp/cpd/baiu/kako_baiu11.html）
  15. Japan Meteorological Agency, 過去の梅雨入りと梅雨明け（東北北部）, 平年 (1991–2020). Read it. Accessed 5 October 2026. 出典：気象庁ホームページ（https://www.data.jma.go.jp/cpd/baiu/kako_baiu12.html）

Changes made. We translated the region names and wrote the dates in English (for example 5月10日頃 as “around 10 May”); the dates themselves are as the agency gives them. 「過去の梅雨入りと梅雨明け」（気象庁）（https://www.data.jma.go.jp/cpd/baiu/kako_baiu01.html）を加工して作成。「過去の梅雨入りと梅雨明け」（気象庁）（https://www.data.jma.go.jp/cpd/baiu/kako_baiu02.html）を加工して作成。「過去の梅雨入りと梅雨明け」（気象庁）（https://www.data.jma.go.jp/cpd/baiu/kako_baiu03.html）を加工して作成。「過去の梅雨入りと梅雨明け」（気象庁）（https://www.data.jma.go.jp/cpd/baiu/kako_baiu04.html）を加工して作成。「過去の梅雨入りと梅雨明け」（気象庁）（https://www.data.jma.go.jp/cpd/baiu/kako_baiu05.html）を加工して作成。「過去の梅雨入りと梅雨明け」（気象庁）（https://www.data.jma.go.jp/cpd/baiu/kako_baiu06.html）を加工して作成。「過去の梅雨入りと梅雨明け」（気象庁）（https://www.data.jma.go.jp/cpd/baiu/kako_baiu07.html）を加工して作成。「過去の梅雨入りと梅雨明け」（気象庁）（https://www.data.jma.go.jp/cpd/baiu/kako_baiu08.html）を加工して作成。「過去の梅雨入りと梅雨明け」（気象庁）（https://www.data.jma.go.jp/cpd/baiu/kako_baiu09.html）を加工して作成。「過去の梅雨入りと梅雨明け」（気象庁）（https://www.data.jma.go.jp/cpd/baiu/kako_baiu10.html）を加工して作成。「過去の梅雨入りと梅雨明け」（気象庁）（https://www.data.jma.go.jp/cpd/baiu/kako_baiu11.html）を加工して作成。「過去の梅雨入りと梅雨明け」（気象庁）（https://www.data.jma.go.jp/cpd/baiu/kako_baiu12.html）を加工して作成。「よくある質問（梅雨）」（気象庁）（https://www.jma.go.jp/jma/kishou/know/faq/faq33.html）を加工して作成。 Edits by Gallivanting Gadabout.