Al-Muttalib bin Hantab (may Allah have mercy on him) narrates that the Prophet (peace and blessings be upon him) used to say when it rained: 'Allahumma-sqina rahmatan, wa la tasqina 'adhaban, wa la bala'an, wa la hadman, wa la gharaqan. Allahumma 'ala al-akami wa manabit al-shajar. Allahumma hawalayna wa la 'alayna' (O Allah, give us a watering of mercy, and do not give us a watering of punishment, nor of calamity, nor one that demolishes houses, nor one that drowns. O Allah, send such rain upon the hills and the forests. O Allah, send it around us and not upon us).
This is mursal.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب صلاة الاستسقاء / 6443