It is narrated from ‘Abbad bin Tamim (may Allah be pleased with him) that he states: The Messenger of Allah (ﷺ) offered the prayer of Istisqa (prayer for rain), and he was wearing a heavy black cloak. He grasped it from below and tried to turn it upwards, and when it became burdensome, he simply turned it over on his shoulders.
Hadith Referenceمسند الإمام الشافعي / كتاب العيدين والأضاحي والاستسقاء / 515
Hadith Takhrijاخرجه ابوداود، الاستسقاء، باب جماع ابواب صلاة الاستسقاء وتفريعها (1164) ۔ والنسائي، الاستسقاء، باب الحال التي يستحب للامام ان يكون عليها اذا خرج (1508) موصولا ۔ وصححه ابن خزيمة (1415)۔