English Translation
Narrated Abbas bin Tamim from his uncle, "I saw the Prophet on the day when he went out to offer the Istisqa' prayer. He turned his back towards the people and faced the Qibla and asked Allah for rain. Then he turned his cloak inside out and led us in a two Rakat prayer and recited the Qur'an aloud in them."
This hadith is from Sahih al-Bukhari, the most rigorously authenticated collection in Islamic scholarship. No editorial opinion is added.