Well, the Hijri date 21 Shawwal 1306 corresponds to the Gregorian date Thursday, 20 June 1889. This date lies in the tenth month of the Hijri year 1306 AH, which is Shawwal of 1306 AH. Both this Hijri and Gregorian date occur on the single day that is Thursday without any doubt. The Arabic date 1306/10/21 is calculated using the Umm Al-Qura calendar and the sighting of the moon. One thing to remember is that this Arabic date may occur on different Gregorian date depending upon the region and country and obviously the moon.
If you are still not sure about the date then you can use our Arabic date converter.
The following is the conversion of the Gregorian date 20 June 1889 to its equivalent Arabic date.
The following is the conversion of the Arabic date 21 Shawwal 1306 AH to its equivalent Gregorian date.
لِّئَلَّا يَعْلَمَ أَهْلُ ٱلْكِتَٰبِ أَلَّا يَقْدِرُونَ عَلَىٰ شَىْءٍۢ مِّن فَضْلِ ٱللَّهِ ۙ وَأَنَّ ٱلْفَضْلَ بِيَدِ ٱللَّهِ يُؤْتِيهِ مَن يَشَآءُ ۚ وَٱللَّهُ ذُو ٱلْفَضْلِ ٱلْعَظِيمِ
That the People of the Scripture may know that they control naught of the bounty of Allah, but that the bounty is in Allah's hand to give to whom He will. And Allah is of Infinite Bounty.
Surah Al-Hadid(57:29)