Japan’s rainy season starts in early summer, between May and July, depending on the region. The period is called Tsuyu (also pronounced baiyu) which translates to “plum rain” as the season coincides with the ripening of Japan’s plums.
The wet weather is caused by cold winds from the north colliding wind warm southern winds which create several weeks of rain. The amount of rainfall varies dramatically from year to year. Some years are exceptionally wet whereas other years barely see any rain.