Since the Islamic year is eleven to twelve days shorter than the Gregorian year, the Islamic new year does not come on the same day of the Gregorian calendar every year. While some Islamic organisations prefer determining the new month (and hence the new year) by local sightings of the moon, most Islamic institutions and countries, including Saudi Arabia, follow astronomical calculations to determine future dates of the Islamic calendar.
There are various schema for calculating the tabular Islamic calendar (i.e. not based on observation), which results in differences of typically one or even two days between countries using such schema and those that use lunar sightings. For example, the The Umm al-Qura Calendar used in Saudi Arabia was reformed several times in recent years. The current scheme has been introduced in AH 1423 (15 March 2002).
A day in the Islamic calendar is defined as beginning at sunset. For example, 1 Muharram 1432 was defined to correspond to 7 or 8 December 2010 in official calendars (depending on the country). For an observation-based calendar, a sighting of the New Moon at sunset of 6 December would mean that 1 Muharram lasted from the moment of sunset of 6 December to the moment of sunset of 7 December, while in places where the New Moon was not sighted on 6 December, 1 Muharram would last from the moment of sunset of 7 December to the moment of sunset of 8 December.
The following dates on the Gregorian calendar correspond to the Islamic new year:
|Islamic Year||Gregorian Date|
|1430 AH||28/29 December 2008|
|1431 AH||17/18 December 2009|
|1432 AH||7/8 December 2010|
|1433 AH||26/27 November 2011|
|1434 AH||14/15 November 2012|
|1435 AH||4/5 November 2013|
|1436 AH||24/25 October 2014|
|1437 AH||13/14/15 October 2015|
Read more about this topic: Islamic New Year