Hadith.1504 - A group of people from Kufa came to Commander of the Faithful Imam Ali ibn Abi Talib عليه السلام and said:
"O’ Commander of the Faithful Imam Ali ibn Abi Talib عليه السلام, pray for us for rain."
Commander of the Faithful Imam Ali ibn Abi Talib عليه السلام called for Imam Hasan عليه السلام and Imam Hussain عليه السلام and said:
"O’ Hassan عليه السلام, Pray."
Imam Hassan عليه السلام supplicated, saying:
"O’ Allah سبحانه وتعالى, stir up the clouds for us, open the doors (of mercy), with abundant water, pouring down and gushing forth. O’ Giver, grant us a deluge that covers and flows abundantly. Open its locks, ease its release, and hasten its bringing forth to water the valleys and uplands, O’ Giver! Let it be rain that pours copiously, that saturates and refreshes, that is beneficial and sufficient, arriving quickly and blessedly. Let it reach everywhere —our plains and mountains, our deserts and towns —so that it lowers our prices, blesses our crops and cities, and shows us a plentiful provision with scarcity removed. Ameen, O’ Lord عز وجل of the Worlds."
Then He عليه السلام said to Hussain عليه السلام, "Pray."
Imam Hussain عليه السلام supplicated, saying:
"O’ Allah سبحانه وتعالى, Giver of goodness from its sources, Sender of mercies from their origins, and Distributor of blessings upon their people, You are the One from whom we seek rain and the One to whom we turn in need. We are sinners and people of transgressions, while You are the One who forgives and is oft-pardoning. There is no god but You. O’ Allah سبحانه وتعالى, send upon us rain in abundance, providing plentiful and refreshing showers, granting life-giving rain, full and pouring down in abundance, with a swift, nourishing flood, a complete outpouring, wide-spreading and far-reaching, soaking all lands. Let it be a mercy from You upon us, O’ Lord عز وجل of the Worlds."
Before Hussain عليه السلام completed his supplication, Allah سبحانه وتعالى sent down rain in abundance.
Salman al-Farsi was asked about this and was told: "O’ Abu Abdullah, is this something they (Imam Hassan عليه السلام & Imam Hussain عليه السلام) were taught?"
He replied: "Woe to you! Did you not hear the words of Messenger of Allah صلى الله عليه وعلى آله وسلم, who said: 'Wisdom flows on the tongues of my Ahlul Bayt.'"