Sahih Al Bukhari Hadith Number 1005

Narrated `Abbad bin Tamim’s uncle: The Prophet (peace be upon him) went out to offer the Istisqa’ prayer and turned (and put on) his cloak inside out.

15  Invoking Allah for Rain (Istisqaa)
Hadith number 1005
Volume no 2
Chapter: 1 (Going out of the Prophet (peace be upon him) to offer Istisqa’ prayer)