Traditionally called minazuki, "the month of water," June gets more rainfall than other months as the rainy season sets in and sweeps upward through Japan. As with cherry blossom season, rainy season begins and ends earlier in the south and starts later and lasts longer in the north. Hokkaido , relatively unaffected by the rainy season, is a safe bet if you want to avoid the rain almost entirely.
The Japanese word for the rainy season, tsuyu or "plum rain," refers to a period when plums ripen on trees as rice fields around rural Japan are flooded by rain. It's the lifeblood of the rice harvest and, by extension, Japan's population. Another noticeable benefit of the season can be seen in the luminous hydrangeas which flourish in the damp weather.
Not all rainy seasons are created equal though: with low annual rainfall, Hokkaido sees a minimal increase in summer rain, while the southern islands of Kyushu and Shikoku get extremely wet. Careful planning can help you stay relatively dry in June.
Rainy days make for a perfect opportunity to visit museums, art galleries, theaters and department stores.
Ginza, in Tokyo , is an area where you can do all of the above. For a definitive cultural experience, visit Kabukiza in Ginza for a kabuki performance. Enthusiasts can opt for a complete five hour schedule with multiple dramas performed, while more casual spectators may prefer seeing just one. Afterwards, you can pop your umbrella and peruse the area's massive department stores and ample culinary options.
Just north of Ginza, Ueno offers an impressive number of museums, often hosting major exhibits from around the world. From big-name French Impressionists to classical antiquities from the Louvre, Ueno has hosted just about anything you can imagine over the years.
With world class facilities all around the country, Japan claims one of the most highly developed aquarium cultures in the world. The Churaumi Aquarium in Okinawa is the biggest and most highly regarded in Japan.
But you needn't go all that way for a first rate experience. Tokyo and other major cities naturally have a variety of options. Tokyo's Sunshine Aquarium in Ikebukuro is an interesting choice on the 10th floor of a high-rise tower.
Iwaki City's Aquamarine Fukushima facility deserves special mention as one of Japan's largest and most lavish aquariums, having reopened shortly after the tsunami in 2011. Osaka , Nagoya , Kyoto , and Hiroshima all add to this long list.
Already a popular destination on its own merits, Hokkaido sees its stock rise in June due to its comparatively low rainfall. Sapporo hosts two major festivals in rapid succession with the Yosakoi Soran Festival bringing colorful dancing processions to Odori Park (June 7-11) and the three day Hokkaido Shrine Festival starting on June 14.