Invoking Allah for Rain (Istisqaa)

Bukhari :: Book 2 :: Volume 17 :: Hadith 136

Narrated Abbas bin Tamim

from his uncle who said, "The Prophet went out to invoke Allah for rain. He faced the Qibla invoking Allah. He turned over his cloak (inside out) and then offered two Rakat and recited the Quran aloud in them."