Reference: http://www.alfawzan.af.org.sa/node/16003
Question: Is it legislated to supplicate [to Allaah] during rainfall; did the Prophet ﷺ or his companions do so?
Response: Yes, when rain would fall, the Prophet ﷺ would say:
«Rain has fallen upon us by Allaah’s Favour and His Mercy; O Allaah make it a beneficial rain cloud [for us]»
And if the rainfall was plentiful, and there was fear that it would cause harm, then [in this case] the Prophet ﷺ would supplicate:
«O Allaah, [let the rain fall] around us and not upon us; O Allaah, [let the rain fall] on the pastures, hills, valleys and the roots of trees»
