Frequently asked questions about the Hijri calendar

When does the month commence according to the Hijri calendar?

The month commences when the new moon is sighted after sunset.

Is it possible to predict when will the new moon be sighted?

Sighting of the new moon depends on the geographical location of the observer and the local climatic conditions, making it difficult (and even impossible) to predict when the new moon will be sighted.

If the new moon is sighted in one geographical location and not in another, when will the month commence?

If two geographical locations share a common horizon, sighting of the new moon in one location is deemed to be the sighting for the other location too. For example, as the new moon is usually sighted at the same time in Mumbai and Pune, these two cities are said to share a common horizon. If the new moon is sighted in Pune but not in Mumbai (perhaps due to cloudy weather), the month will be deemed to commence in Mumbai too, based on the sighting in Pune.

When does the month end according to the Hijri calendar?

The month ends when the new moon is again sighted after sunset.

What is the length of a month in the Hijri calendar?

The month can comprise of 29 or 30 days in the Hijri calendar. It cannot be shorter than 29 days nor longer than 30 days. Note that the average length of the astronomical lunar month is approximately 29.5 days.

What happens when it is not possible to sight the new moon?

If the new moon cannot be sighted due to climatic conditions, the preceding month will be deemed to comprise of 30 days, after which the next month will commence.

Why does the month in the Hijri calendar not commence when the new moon occurs?

The new moon can occur at any time of the day, as conjunction (when the sun and the moon are aligned) can (and does) occur at different times every month. For example, the new moon according to the local time in Mumbai occurred on 8 April 2024 at 11:50 pm, while the next new moon will be on 8 May 2024 at 8:51 am. If commencement of the new month is linked to the occurrence of the new moon, the month would start at different times every month, and the day in which conjunction occurs would have two dates.

Is the Hijri date the same across the world on any given day?

As sighting of the new moon at a particular geographical location depends on its longitude, the new month may begin a day (or two) earlier in western regions than in regions in the east. Thus, the Hijri date in Mumbai is usually (but not necessarily always) a day behind that in Makkah (and other regions lying to the west).

To know more about the Hijri calendar, click here.

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