The fasting for the Islamic month of Ramadan will begin for Thai Muslims on Thursday.
The office of the Chularatchamontri, formally known as the Sheikhul Islam Office for Thailand, said efforts to spot the new moon from a mountain in the South had failed. This pushed back the fasting period by a day.
"The first day of Ramadan fasting will be Thursday, May 17," the official statement said.
The annual month of daytime fasting and focus on the religion coincides this year with the holding of the three-day annual Muslim Fair at the grounds of the National Mosque in Bangkok's Nong Chok district.
The fair was opened Monday by His Majesty King Maha Vajiralongkorn Bodindradebayavarangkun and the Chularatchamontri, Sheikul Islam Aziz Phitakkumpon.
Prime Minister Prayut Chan-o-cha is scheduled to close the fair on Thursday evening.
The full text of the decree setting the date for the start of Ramadan:
