Hadith.1503 - Imam Jafar ibn Muhammad Al-Sadiq عليه السلام was asked about why The Prophet صلى الله عليه وعلى آله وسلم would turn his cloak around when he prayed for rain (Istisqa').
Imam عليه السلام said: "It was a sign between him and his companions, indicating that drought had turned into abundance."