Tsuyu - Rainy Season

Early summer is the rainy season in most parts of Japan. Tsuyu (or Baiyu) is what the Japanese call the rainy season, it means plum rain (plums ripen at around the same time). The rainy season is caused by the collision of cold northerly and warm southerly air masses, resulting in a relatively stable bad weather front over Japan. The rainy season last from the beginning of June to mid-July, depending on region. Earlier for Okinawa and Hokkaido is barely effected by it at all. In Tokyo it usually from around June 8 to July 20. It does not usually rain every day during the rainy season and the amount of rainfall varies. A movie that I recommend everyone see called Ima, ai ni yukimasu has the rainy season as a major part of the plot.

Teru teru bozu (Teru is a Japanese verb which describes sunshine, and bōzu is a Buddhist monk) are often seen during the rainy season. Teru teru bozu are small doll like charms made with a ball or wad of stuffing and a piece of white cloth or paper tied just below. They are hung as a charm to invite good weather. If the weather is good they maybe given faces. To make it rain occasionally you will see them with either black heads or hung upside down. In the movie mentioned above, the little boy hangs them upside down to bring rain. In Azumanga Doiah, a couple of the characters hang Chiyo-chan (one of the main cast members) upside down outside the window as a Teru teru bozu.

There is also a Warabe uta (song like nursery rhyme) associated with teru teru bozu:

Teru-teru-bozu, teru bozu
Do make tomorrow a sunny day
Like the sky in a dream sometime
If it's sunny I'll give you a golden bell

Teru-teru-bozu, teru bozu
Do make tomorrow a sunny day
If you make my wish come true
We'll drink lots of sweet rice wine

Teru-teru-bozu, teru bozu
Do make tomorrow a sunny day
But if it's cloudy and you are crying (i.e. it's raining)
Then I shall snip your head off

Some people also flip a shoe into the sky, if it lands on its face it would be sunny tomorrow. Osaka does this in Azumanga Daioh, it happens to land on a moving vehicle so she does not find out via shoe toss method if it will be sunny the next day.