أَخْبَرَنِي عَمْرُو بْنُ عُثْمَانَ، قَالَ حَدَّثَنَا الْوَلِيدُ، عَنِ ابْنِ أَبِي ذِئْبٍ، عَنِ الزُّهْرِيِّ، عَنْ عَبَّادِ بْنِ تَمِيمٍ، أَنَّ عَمَّهُ، حَدَّثَهُ أَنَّهُ، خَرَجَ مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم يَسْتَسْقِي فَحَوَّلَ رِدَاءَهُ وَحَوَّلَ لِلنَّاسِ ظَهْرَهُ وَدَعَا ثُمَّ صَلَّى رَكْعَتَيْنِ فَقَرَأَ فَجَهَرَ ‏.‏

It was narrated from Abbad bin Tamim that : His paternal uncle had told him that he went out with the Messenger of Allah (PBUH) to pray for rain. He turned his rida' around, and turned his back to the people, then he prayed two rak'ahs and recited loudly. Translation Not Available

Book reference: Sunan An Nisai Book 17 Hadith 1509
Web reference: Sunan An Nisai Volume 2 Book 17 Hadith 1510