The Prophet ﷺ prayed for rain, pointing toward the sky with the backs of his hands.
أن النبي ﷺ استسقى، فأشار بظهر كفيه إلى السماء.
Muslim reported it in the Book of Rain Prayer (896), from Abd bin Humayd, who said, Hasan bin Musa told us, who said, Hammad bin Salama told us, from Thabit, from Anas, as mentioned above.Nawawi said in his commentary on Sahih Muslim, "A group of our fellow scholars and others said, the sunnah in every supplication for the removal of a calamity, such as drought and the like, is to raise one's hands with the backs of the palms facing the sky, while when supplicating to ask for something and obtain it, the palms should face the sky. They cited this hadith as evidence."