Invoking Allah for Rain (Istisqaa)

Bukhari :: Book 2 :: Volume 17 :: Hadith 147

Narrated Ibn 'Umar:

(The Prophet) said, "O Allah! Bless our Sham and our Yemen." People said, "Our Najd as well." The Prophet again said, "O Allah! Bless our Sham and Yemen." They said again, "Our Najd as well." On that the Prophet said, "There will appear earthquakes and afflictions, and from there will come out the side of the head of Satan."