Upon hearing thunder

سُبْحَانَ الَّذِيْ يُسَبِّحُ الرَّعْدُ بِحَمْدِهِ وَالْمَلَائِكَةُ مِنْ خِيْفَتِهِ

Glory is to Him Whom thunder and angels glorify due to fear of Him.

Subhaanal-lathee yusabbihur-ra'du bihamdihi walmalaa'ikatu min kheefatihi.

Whenever Abdullah bin Zubair (RA) would hear thunder, he would abandon all conversation and say this supplication.