ENOfficial
‘A’isha said that God’s messenger used to count the days in Sha'ban in a manner he did not practise any other month, then fasted when he saw the new moon of Ramadan; but if the weather was cloudy he counted thirty days and then fasted. Abu Dawud transmitted it.
Source: sunnah.com
Other translations
Arabic
وَعَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا قَالَتْ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَتَحَفَّظُ مِنْ شَعْبَانَ مَالَا يَتَحَفَّظُ مِنْ غَيْرِهِ. ثُمَّ يَصُومُ لِرُؤْيَةِ رَمَضَانَ فَإِنْ غُمَّ عَلَيْهِ عَدَّ ثَلَاثِينَ يَوْمًا ثُمَّ صَامَ. رَوَاهُ أَبُو دَاوُد
sunnah.com