expression, godan verb (-ru)
Basic weather expression with 雨 as the subject and 降る as an intransitive verb; it can be inflected like 降る, as in 雨が降った and 雨が降っている.
午後から雨が降るそうです。
I hear it will rain from the afternoon.
昨日は一日中雨が降っていた。
It rained all day yesterday.