入梅にゅうばい (nyuubai)

今年ことしの 入梅にゅうばいは 6 月がつ 10 日とおかでした

The rainy season began on June 10th this year.

入梅になった. The rainy season has set in.当地では入梅は 6 月です. In these parts the rainy season starts [sets in] in June.もうじきに入梅になる. It will not be long before the rainy season sets in.梅雨の時季が始まることを梅雨入り（入梅）、梅雨が終わって夏になることを梅雨明け（出梅）と言う。

If the season of baiu begins, it is called "tsuyuiri (or 'nyubai')" and if it ends and the summer begins it is called "tsuyuake (or 'shutsubai')."