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
← Previous Hadith His father said: "One of the governors sent me to Ibn Abbas to ask him about the prayer for rain. He said: 'What kept him from asking me? The Messenger of Allah (ﷺ) went out humbly, (dressed) in a state of humility, submissiveness and beseeching, and he prayed two rak'ahs as in the Eid prayer, but he did not deliver a Khutbah like this Khutbah of yours.'"

Sunan an-Nasa'i Book 17, Hadith 18 Next Hadith → 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