عَنْ عَبْدِ اللَّهِ بْنِ زَيْدٍ قَالَ: خَرَجَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بِالنَّاسِ إِلَى الْمُصَلَّى يَسْتَسْقِي فَصَلَّى بِهِمْ رَكْعَتَيْنِ جَهَرَ فِيهِمَا بِالْقِرَاءَةِ وَاسْتَقْبَلَ الْقِبْلَةَ يَدْعُو وَرَفَعَ يَدَيْهِ وَحَوَّلَ رِدَاءَهُ حِينَ اسْتَقْبَلَ الْقِبْلَةَ

Anas said the Prophet was not accustomed to raise his hands in any supplication he made except when praying for rain. He would then raise them high enough for the whiteness under his armpits to be visible. (Bukhari and Muslim.)