Sahih Bukhari Volume 002, Book 017, Hadith Number 130.
Hadith Section/Book: Sahih Bukhari Sahih Bukhari Book 17. Invoking Allah for Rain (Istisqaa)
Narated By Anas bin Malik : A man came to Allah's Apostle and said, "O Allah's Apostle! Livestock are destroyed and the roads are cut off. So please invoke Allah." So Allah's Apostle prayed and it rained from that Friday to the next Friday. Then he came to Allah's Apostle I and said, "O Allah's Apostle! Houses have collapsed, roads are cut off and the livestock are destroyed." So Allah's Apostle (p.b.u.h) prayed, "O Allah! (Let it rain) on the tops of mountains, on the plateaus, in the valleys and over the places where trees grow." So the clouds cleared away from Medina as clothes are taken off.