The month of Muharram marks the beginning of the Islamic Calendar. The coming ‘Islamic New Year‘, 1 Muharram 1443 AH is marked by the moon conjunction on Ahad, 8 August 2021 at 13:50 UTC. However, the crescent moon or hilal of the Muharram month will not be visible on that evening for most part of the world. Many muslims use the appearance of the young crescent moon as the official start of the lunar month.
The crescent moon visibility map below shows the possibility of sighting the crescent moon on Ahad or Sunday.
However, the moon will be above the horizon after sunset in Makkah, Saudi Arabia on that evening. Therefore, based on this condition, the Ummul Qura Calendar of Saudi Arabia puts Monday, 9 August 2021 as the beginning of the new islamic year 1443 AH.
For those using moon sighting to start the islamic months, the crescent moon of 1 Muharram 1443 AH will be easier to sight on the evening of Monday. And based on the crescent moon visibility map below, most part of the world would be able to see the crescent moon. Therefore, for most part of the world, the Islamic New Year, 1 Muharram 1443 AH would correspond to Tuesday, 10 August 2021.