Musnad Ahmad 952:5

Harun ibn Ma'ruf narrated to us, he said: Ibn Wahb said: Haywah informed us, from Ibn al-Had, from Muhammad ibn Ibrahim al-Taymi, from Umayr, the freed slave of Abi al-Lahm: That he saw the Messenger of Allah (peace and blessings of Allah be upon him) seeking rain at the Stones of al-Zayt, near al-Zawra', while standing. He was supplicating and seeking rain, raising his hands, not exceeding his head with them, with the palms of his hands facing toward his face.