After reviewing crescent moon sighting reports from across the country, the Supreme Court of Saudi Arabia announced that Tuesday, 15 September 2015 is the first day of Dhul-Hijjah 1436 AH. Therefore, the day of Wuquf, 9 Dhul-Hijjah 1436 AH (day of Arafah) is on 23 September 2015 and Eid ul Adha 1436 AH is on 24 September 2015. This announcement puts the Eid ul Adha a day latter than the official civil calendar of Ummul Qura.
Source: Saudi Press Agency, AlArabiya