(1) باب رَفْعِ الْيَدَيْنِ بِالدُّعَاءِ فِي الاِسْتِسْقَاءِ
Anas b. Malik reported that the Messenger of Allah (ﷺ) prayed for rain pointing the back of his hands to the sky.
Reference: Sahih Muslim 895 b
In-book reference: Book 9, Hadith 6
USC-MSA web (English) reference(deprecated numbering scheme): Book 4, Hadith 1952