It is narrated from Hazrat Samurah (may Allah be pleased with him) that on the day of rain during the Battle of Hunayn, the Prophet (peace and blessings be upon him) told the people to pray in their tents.
Hadith Referenceمسند احمد / أول مسند البصريين / 20170
Hadith Gradingحکم دارالسلام:صحيح لغيره، وهذا إسناد ضعيف، الحسن مدلس وقد عنعن