Rainy Season in Japan (Tsuyu)

Japan's rainy season — tsuyu, written 梅雨 and also read baiu — runs from roughly early June to mid-July across the main islands. It reaches Okinawa in the second week of May, the mainland in the first week of June, northern Tohoku by mid-month, and Hokkaido not at all. In any one place it is about six weeks of humid, changeable weather: grey mornings, heavy bursts in the afternoon, and more dry stretches than the name suggests. It is also the quietest and best-value month of the warm half of the year, which is the real case for coming.

When is the rainy season in Japan?

The Japan Meteorological Agency declares tsuyu region by region, and the front works its way north: Okinawa around 10 May, southern Kyushu at the end of the month, Kansai, Tōkai and Kantō in the first week of June, and northern Tohoku by the middle of it. It lifts in the same order — late June in the far south, the third week of July across most of the country, the end of the month in the north. The calendar below gives the Agency's own average dates for each of its twelve rainy-season regions, earliest first.

Two things about those dates matter before you plan around them. The Agency publishes each one as an approximation, because the season turns over about five days rather than on a morning; and it confirms both ends only after the summer, once the whole pattern can be read. What exists in advance is a forecast, not a date.

What is tsuyu, exactly?

Tsuyu is a front, not a monsoon. The baiu zensen (梅雨前線) is a stationary boundary where cool, damp air over the Sea of Okhotsk meets the warm, wet air of the Pacific high pushing up from the south. It parks over the archipelago for weeks and slides slowly north as that high strengthens. When the high finally wins, the front is shoved away to the north, and 梅雨明け — the end of the rainy season — is followed within days by the full heat of Japanese summer.

The name means plum rain: the rains arrive as the ume plums ripen. Not every year behaves, and Japanese has words for the ways it doesn't. A 空梅雨 (karatsuyu) is a rainy season that barely rains. A 戻り梅雨 (modorizuyu) is a return to rainy-season weather after the season has been declared over. Hokkaido's occasional damp June spells are called 蝦夷梅雨 precisely because they are not the real thing — the front dissolves before it gets that far north, which is why the island has no declared season at all.

How much does it really rain?

Less than you are picturing, and rarely all day. A tsuyu day is usually overcast, in the low to mid twenties °C with humidity in the seventies — noticeably kinder than the mid-30s of late July — and the rain comes in heavy bursts rather than a steady grey drizzle. Losing a whole day to rain happens; far more common is a wet morning that clears by lunch, or a bright afternoon that ends in a downpour. So the workable approach is not to plan the fortnight but to keep one indoor option in reserve each day and check the forecast for the prefecture you are in the night before.

One part of the season deserves proper respect. The late stage, from the end of June into July, is when Japan's heaviest rainfall events happen, and the Agency issues heavy-rain warnings regularly. Take them at face value: trains stop, and riverside and mountain roads close. On the great majority of trips this amounts to one rearranged day.

Why June is the emptiest month worth travelling in

Here is what the weather headlines bury. June sits between Golden Week and the school holidays that fill July and August, and the reputation of the rain keeps a great many people away outright — so travel across the country drops off sharply, and the outdoor sights that define a Japanese itinerary are as close to empty as they ever get. Fushimi Inari's tunnel of torii, the Arashiyama bamboo grove, Nara's deer park, the lantern-lit approach to Kiyomizu-dera, the floating torii at Miyajima, the thatched roofs of Shirakawa-gō: shoulder to shoulder in April and November, and in late June largely yours. Room rates and airfares follow the same curve down, and the tours that sell out months ahead in spring have same-week availability.

Our month-by-month comparison rates June medium on both crowds and prices, which nothing else in the warm half of the year manages. If you are coming for the places themselves rather than for cherry blossom or autumn colour, that is a very good trade.

What actually looks better in the rain

Wet weather is not a compromise everywhere. A number of Japan's most-loved places were built for rain, or only come into their own once the stone is dark and the air is heavy.

• Hydrangeas — ajisai are the flower of the rainy season, and they peak in the second half of June. Meigetsu-in in Kamakura is known simply as the hydrangea temple; Hase-dera, up the road, banks them along a hillside path above the sea; Mimuroto-ji in Uji counts them in the tens of thousands. Rain is not a spoiler here — it is the condition the whole season is named for.
• Moss gardens — Saihō-ji, the Kokedera, and Gion's Gio-ji in western Kyoto; Sanzen-in out at Ōhara. Dry moss is flat and grey. Wet moss is luminous, and these gardens hit their peak in exactly the weeks most visitors avoid.
• The great stroll gardens — Kenroku-en in Kanazawa, Kōraku-en in Okayama, Ritsurin-kōen in Takamatsu. Rain darkens the stone, doubles every lantern and bridge in the ponds, and empties the paths.
• Temple verandas — one of the quieter pleasures of a Japanese summer is sitting on the boards of a Kyoto temple watching rain come off the eaves onto the moss. The deep overhangs exist for this weather.
• Yakushima — a temperate rainforest that gets rain most days of the year, and the mossed-over ravine at Shiratani Unsuikyō is the reason to go. Here the rain is not the obstacle, it is the landscape.
• Onsen towns — Kinosaki, Kurokawa, Ginzan, Beppu. An outdoor bath in falling rain, with steam coming off the water, is the single best argument for travelling in June, and the ryokan that make their name on it are cheaper this month.
• Cities after dark — Shinjuku, Shibuya, Dōtonbori. Wet asphalt doubles every sign in the street, which is why the photograph at the top of this page was taken in the rain rather than in spite of it.
• Covered markets and arcades — Nishiki in Kyoto, Ōmichō in Kanazawa, Kuromon in Osaka, and the roofed shōtengai in every city, where you can spend an afternoon eating without ever opening an umbrella.

And for the afternoons when it is genuinely coming down, Japan is better equipped than almost anywhere: world-class aquariums, the digital-art museums, the great national collections, department-store food halls, neighbourhood sentō, a kimono fitting, a cooking class. Our things to do by prefecture lists what is indoors and bookable wherever you happen to be standing.

Where to go to miss it altogether

• Hokkaido — the one part of Japan with no declared rainy season. June there is green, cool and comfortable, and it is the month before the summer crowds arrive.
• Okinawa and the southern islands — their tsuyu comes early and goes early, lifting around 21 June. From the last week of June the beaches are open and dry while the mainland is still under cloud.
• Up high — the mountain resorts sit above much of the humidity. Karuizawa, Hakone and Kamikōchi are several degrees cooler than the cities and are at their greenest now.

What to bring, and how to travel in it

• A folding umbrella, and no guilt about buying another. Every convenience store sells a clear plastic one for pocket change; almost every hotel lends them; entrances have stands and sleeves for them.
• Shoes that survive a puddle, and a second pair. Wet trainers do not dry overnight in eighty per cent humidity — most hotels have a coin laundry with a dryer.
• Quick-dry layers rather than more layers. It is warm rain; the problem is humidity, not cold.
• A day plan with an indoor half. Pair the garden with the museum down the road and let the morning decide the order.
• The forecast, the night before. Tsuyu weather is local and short-lived, so a look at your prefecture's forecast the evening before is worth more than any long-range plan.

Trains, museums, restaurants and festivals all run as normal — nothing about Japan shuts for rain. Pack for it, plan loosely around it, and June hands you the country with the crowds turned off.