From early May to late July, most of the areas in Japan experience a gloomy rainy season known as “Tsuyu” or “Baiu.” Meteorologically, it’s caused by the collision of warm, high-pressure fronts coming from the south and cold, high-pressure fronts staying in the north. Thus, tsuyu starts in the southern part of Japan and moves up north. (See the table for the average period of tsuyu in each region.)
Unlike rainy seasons in other areas of the world, tsuyu is rarely accompanied by squalls or showers. Instead, it rains constantly. Consequently, it sometimes causes serious landslides. What bothers people most, though, is the humidity. It’s so horrible that it makes things get moldy and food more perishable. It is actually the season most people suffer from food poisoning. Most of the Japanese hate tsuyu for this reason.
Tsuyu does not, however, bring about only depressing things. It’s a blessed season for crops. Thanks to the abundant rainfall, crops grow very well, resulting in a rich harvest. Actually, Japanese people write “tsuyu” with the kanji (Chinese character used in Japan) meaning “plum rain” since plums ripen during this season, although the original kanji when they imported the word and concept from China was “mold rain.”
Tsuyu is deeply embedded in Japanese culture, so no matter how gloomy it is, Japanese people appreciate this season and try to enjoy it as much as possible. Many sightseeing places maximize the soft focus effect that the misty rain creates for viewing scenic areas. Also, ajisai (hydrangea) bloom in this season, and Japanese people strongly associate this flower with tsuyu. If you visit Ajisai-dera (Hydrangea Temple) in Kamakura, Kanagawa Prefecture, during this season, you will understand the Japanese sentiment and enjoy the beautiful, misty view.
In modern Japanese society, people have figured out how to spend the month and a half of this damp season more comfortably. Hi-tech dehumidifiers and air conditioning units with dehumidifying functions continue to be developed, while the fashion industry tries to encourage people to go out by providing a variety of rainproof items: brightly colored raincoats, rubber boots, bags, hats, and umbrellas. Polka dots, flowers, frogs, and snails are popular patterns in this season. After tsuyu, Japan enters summer. The sun always shines after the rain.