Riyadh: The Islamic holy month of Ramadan will begin Thursday in Saudi Arabia, authorities said.
"The first day of the holy fasting month of Ramadan falls on Thursday corresponding to May 17, 2018," the Royal Court said in a statement published by SPA.
The start date is set by both lunar calculations and physical sightings which determine when the last day of one lunar month ends and a new one begins.
Ramadan is a holy month for the world's nearly 1.5 billion Muslims, who practise the ritual of dawn-to-dusk fasting and prayers.
Tradition holds that it was during Ramadan that the Prophet Mohammed started receiving revelations of the Muslim holy book, the Quran.
Ramadan is one of the five "pillars" of Islam.