Predicting the date of Idd-Ul-Fitr

 By MUNGAI KIHANYA

The Sunday Nation

Nairobi,

18 August 2013

The Holy Month of Ramadhan has now passed but, as usual, it has left behind some quiet grumbling amongst some non-Muslims, especially in the business community. The question that bothers many is whether it is possible to determine the date of Idd-Ul-Fitr more than a few days in advance.

Normal practice in Kenya is that the government Gazettes the date of the official Idd public holiday about a week ahead. This makes it very difficult for people to plan events and business meetings.

But looking at the nature of the Islamic Calendar, I think that the date of the official Idd public holiday can be determined many years, or even centuries, in advance. We don’t have to wait until we are a few days away!

The Islamic calendar is based on the phases of the moon and the motion of this celestial body is know very accurately. The duration from one Full Moon to the next has been measured over many centuries and it is known to be 29 days, 12 hours, 44 minutes and 2.877 seconds!

Now the Islamic calendar has 12 lunar months; that is, each month begins with first crescent of the new moon. Thus the Islamic year has 354.37 days. In practice, it turns out to be 354 days sometime, and 355 at others. Thus it is 10 or 11 days shorter than the 365 of the international solar year.

The fluctuation in length should not be cause for worry; after all, even the international year fluctuates between 365 and 366 days! However, because the Islamic year is more than a week shorter than the international one, the date of Idd shifts backwards by between 10 and 11 days on the calendar each successive year.

For example, Idd was on 19th August last year [this was a Sunday, so the official public holiday was extended to Monday 20th] while this year it was 10 days earlier on the 9th of the same month.

With that in mind, we can make our first guess of the date of Idd 2014: it will be 10 or 11 days earlier than this year. That is, on the 29th or 30th July 2014. But we can get a better estimate by counting the days forwards starting fro the real Idd-Ul-Fitr this year.

The 2013 Holy Ramadhan fast ended on the evening of Wednesday 7th August. The Islamic year is 354 days, 8 hours, 48 minutes and 35 seconds long, that is, 29 days, 12 hours, 44 minutes and 2.877 seconds multiplied by 12 months.

Counting these days and hours starting from August 7^th takes us to about 2am on the morning of July 27 2014. Thus chances are that the new crescent moon marking the end of Ramadhan 2014 will be sighted in the evening of July 27, meaning that Idd-Ul-Fitr will most likely fall on July 28. Therefore, we can go ahead and mark that day as the official public holiday so that businesses and government offices can make their plans with that information at hand.