The first day of Eid Al Fitr is expected to fall on Monday, May 2 in most Islamic countries, according to the International Astronomical Centre.
The centre said the crescent of the Shawwal moon would be seen on Saturday April 30, corresponding to 29 Ramadan, reported the state news agency Wam.
Emirates Astronomical Society has also forecast that Eid Al Fitr and the first of Shawwal will be on May 2.
Mohammad Shawkat Odeh, director of the International Astronomical Centre, said that in places that began Ramadan on Sunday, April 3, the crescent of Shawwal will be seen on Sunday, May 1. These countries include Indonesia, Malaysia, Brunei, India, Bangladesh, Pakistan, Iran, Oman, Jordan, Morocco and Ghana.
He said seeing the crescent on Saturday, April 30 would be impossible because the Moon will set before the Sun. By that stage, he said, countries will have completed 30 days of Ramadan, meaning Eid Al Fitr will start on May 2.
In countries that will witness the crescent on May 1, including Australia and neighbouring regions, sighting the Moon that day will not be possible. It will be visible by telescope in Central and West Asia, most of Europe and southern Africa, he said.