اللَّهُمَّ اغْفِرْ لِي
Allahummagh-fir li (and any personal du'a)
O Allah, forgive me. (Du'a during rainfall is accepted.)
The Prophet ﷺ said that du'a is accepted at certain times, and one of them is during rainfall. Rain is a manifestation of Allah's mercy descending from the sky — and when mercy is descending, your requests ride up with it. Any personal du'a made while rain is falling carries extra weight. The scholars recommend not wasting a single rainy moment without lifting your hands.
Related Du'as
اللَّهُمَّ صَيِّبًا نَافِعًا
O Allah, let it be a beneficial rain.
Sahihاللَّهُمَّ حَوَالَيْنَا وَلَا عَلَيْنَا، اللَّهُمَّ عَلَى الْآكَامِ وَالظِّرَابِ وَبُطُونِ الْأَوْدِيَةِ وَمَنَابِتِ الشَّجَرِ
O Allah, around us and not upon us. O Allah, upon the hills, the elevated lands, the valleys, and the places where trees grow.
Sahihاللَّهُمَّ لَا تَقْتُلْنَا بِغَضَبِكَ وَلَا تُهْلِكْنَا بِعَذَابِكَ وَعَافِنَا قَبْلَ ذَلِكَ
O Allah, do not kill us with Your anger, do not destroy us with Your punishment, and grant us safety before that.
Hasanاللَّهُمَّ إِنِّي أَسْأَلُكَ خَيْرَهَا وَأَعُوذُ بِكَ مِنْ شَرِّهَا
O Allah, I ask You for its good and seek refuge in You from its evil.
Sahih