Facts of Eid al-Fitr and Christmas Day Will Happen Together in 2031

VIVA – As usual, Christmas and Eid al-Fitr happen at different times. However, recently, there has been a lot of issues on social media says that these two big days will happen simultaneously on December 25, 2031. Well, here’s the truth.

The Space Research Center of the National Research and Innovation Agency (BRIN) reports that the Hijri calendar uses the chronological or lunar system, which means it is based on the circulation of the Moon around the Earth.

Eid al-Fitr is one of the Muslim big days that use the Hijri calendar. It falls at the beginning of the month of Shawwal, the tenth month of the Hijri calendar. Every year, the date of Eid al-Fitr that uses the Gregorian calendar can be different, even earlier.

"This is because the length of the Hijri year is 12 times the period of the Moon orbiting the Earth, which is 354.367 days. While the length of the Gregorian year is based on the period of the Earth orbiting the Sun, which is 365.242 days," BRIN explained as quoted from VIVA Tekno, on Wednesday, January 4, 2023.

So, there is a difference of about 11 days each year. In fact, when the holiday falls at the beginning of the Gregorian year, Eid al-Fitr can be held twice in one Gregorian year, with the second Eid al-Fitr falling at the end of the Gregorian year.

This phenomenon is also repeated every 32 to 33 years. The beginning of Shawwal 2031 falls on January 23, 11:30 am in Western Indonesian Time/12:30 pm in Central Indonesian Time/1:30 pm in Eastern Indonesian Time. 

For observations at that time, the evening in Indonesia varies between - 0.58 degrees (Merauke, Papua) to + 2.02 degrees (Sabang, Aceh). Meanwhile, the hilal-Sun geocentric elongation angle varies between 5.10 degrees (Merauke) to 6.14 degrees (Sabang).

With the hilal visibility criteria that Indonesia currently uses (topocentric altitude> 3 degrees and geocentric elongation.

The closest New Moon phase on December 25, 2031, falls on December 14 at 4:05 pm in Western Indonesian Time/5:05 pm in Central Indonesian Time/6:05 pm in Eastern Indonesian Time which is the ijtimak of the beginning of Ramadan 1453 Hijri.

This means that December 25, 2031, falls on the 10th of Ramadan 1453 Hijri. Meanwhile, 1 Shawwal 1453 Hijri is expected to fall on January 14, 2032, so that Eid al-Fitr does not coincide with Christmas in 2031.

"Throughout Indonesia's independence, Eid al-Fitr has coincided with Christmas twice. First, on December 21, 1968. Second, on December 27, 2000. The next events will occur on December 23, 2033, and December 29, 2065," BRIN explained.