1.
early summer rain; seasonal rain
The long, continuous rain that falls in early summer (around May-June in the lunar calendar). Associated with the rainy season.
五月雨の季節になった。
The early summer rain season has arrived.
2.
intermittent; sporadic; in a trickle
Used figuratively to describe something happening intermittently or in scattered intervals, like falling rain.
五月雨式に報告が届く。
Reports arrive sporadically.
申し訳ありません、五月雨になってしまいました。
I'm sorry this came in bits and pieces.
五月雨 originally refers to rain in the fifth month of the lunar calendar (roughly June).
LITERARY USAGE:
A poetic term often found in classical literature and haiku.
MODERN BUSINESS USAGE:
五月雨式 describes:
- Sending emails/messages in multiple parts
- Making payments in installments
- Delivering items in batches
Note: Using 五月雨式 in business often carries an apologetic nuance, implying inconvenience caused by the sporadic nature.