General Behavior (Kitab Al-Adab)

Dawud :: Book 41 : Hadith 5080

Narrated Aisha, Ummul Mu'minin:

When the Prophet (peace_be_upon_him) saw a cloud formation in the sky, he left work, even if he were at prayer, and then would say: "O Allah! I seek refuge in Thee from its evil. " If it rained, he would say: "O Allah! send a beneficial downpour."