the start of the rainy season, the onset of the rainy season
今年は、梅雨入りが早かったね。
The rainy season started early this year, didn't it?
もうすぐ梅雨入りだ。
The rainy season will start soon.
梅雨入りは来週以降になりそうだ。
It looks like the rainy season will begin sometime next week or later.
今年は、梅雨入りが早いですね。
The rainy season is starting early this year, isn't it?