When it rained the Messenger of Allah would say: "Allahummaj'alhu Sayyiban nafi`a. (O Allah, make it beneficial rain)."
Sunan an-Nasa'i Book 17, Hadith 20
← Previous Hadith The Prophet (ﷺ) went out and prayed for rain, then he prayed two rak'ahs in which he recited loudly.

Sunan an-Nasa'i Book 17, Hadith 19 Next Hadith → "The Messenger of Allah (ﷺ) said: "Allah, the Mighty and Sublime, said: I have never sent down My favor to My slaves but a group of them became disbelievers who say; "The stars and by stars.'"

Sunan an-Nasa'i Book 17, Hadith 21