Precipitating Factors

Coming into bloom in June, the hydrangea is the most familiar symbol of Japan’s rainy season.

When it comes to widely held meteorological beliefs, none among the Japanese comes even close to the assertion that their country has four distinct seasons. More than one non-Japanese commentator has in fact noted the frequency with which this point is averred. Of course, it would be impossible to underestimate the role that the seasons play in Japanese aesthetics—from poetry and the tea ceremony to flower arrangements and all those delights of the dinner table. Accordingly, a common lament among Japanese living in equatorial climes is not that of having to cope with the oppressive heat, but being unhinged from the familiar progression of the seasons.

Despite all this, though, there are pretty solid grounds for the contention that Japan—at least the bit of it south of the northern main island of Hokkaido—possesses not four seasons, but five. The timing does depend on the location, and there are also annual variations, but from around the beginning of June to the middle of July, Japan finds itself in the throes of its rainy season.

That season is known as tsuyu or baiu in Japanese, which translates poetically as “plum rain” (or with greater technical accuracy as “apricot rain”). This name derives from the fact that it coincides with the ripening of that fruit. Though its name comes from another plant, the most familiar symbol of Japan’s rainy season is the hydrangea. This native of Japan and elsewhere in eastern Asia comes into bloom in June, and the flowers deepen in color as the season progresses. So strong is the association of the flowers with this time of year that the mention of hydrangeas in poetry is taken as an allusion to the rainy season.

Though it generally lasts everywhere around six weeks, the rainy season in Okinawa, in the far southwest, usually begins in early May, whereas at the northern end of Honshu, Japan’s largest main island, it normally starts about a month later. As might be supposed, Japan’s rainy season is no isolated phenomenon but is part of the East Asian monsoon, which also affects Indochina, the Philippines, China and Korea. That monsoon is in turn closely related to the famed Indian monsoon.

However, despite the monsoonal connection, the time of year in Japan that brings joy to the hearts of its umbrella manufacturers is no biblical deluge. Naturally, rain is no inconspicuous feature during its very own season. It certainly can happen that there are days on end when, as in Bladerunner, it just never seems to stop raining. But there are also often spots of rather pleasant weather, which can make for an agreeable period of respite before the long, hot, humid machinery of Japan’s summer grinds into gear.

As well as among makers of rain gear, the rainy season is a welcome occasion for Japan’s rice farmers and their very thirsty crops. For others in the country, that season brings other inconveniences apart from having to trudge out each morning with their best friend of an umbrella firmly in their grasp. All that humidity tends to make things just perfect for the growth of mold. Mold in Japan appears to take a bottom-up approach to life in that shoes are its preferred point of attack. No few numbers of people have discovered that mold has magically placed a conspicuous white layer upon previously black shoes, whereas a similar, though inverse, metamorphosis can suddenly transform those pristine white sneakers into rather terrifying black beasts.

Like the hot summer that follows, the rainy season is not an especially popular time of year. In addition to the practical problems caused by the high humidity, the dampness also tends to, well, dampen the spirits. The Japanese traditionally dealt with this by resorting to very hot baths, believing that a good, long soak would stimulate the circulation and functions of internal organs and generally bring a little zest into their lives. And though the rainy season may not see Japan at its picture-postcard best, there is indeed a particular loveliness to sitting in an open-air hot spring, reveling in its thermal succor, viewing the mist suspended above the trees and listening to the gentle patter of the falling rain.

David Capel is a journalist living in Tokyo.

Note: This article first appeared in the May/June 2019 issue of the Japan Journal. Posted to TJJ Online June 2, 2020. Updated May 28 2021.

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