Why Your MUIS Prayer Time Is Different From Your Neighbour's.

Open five different Muslim prayer apps in Singapore right now. Chances are you'll see five different times for Fajr. One says 5:41am. Another says 5:53am. A third says 5:47am. All three claim to use the same astronomical formulas. So where does the 12-minute gap come from?

The answer lies in a single number that most Muslims have never heard of: the solar depression angle. Understanding it will change how you think about prayer times forever.

It starts with twilight

Prayer times aren't arbitrary. They're calculated from the position of the sun relative to the horizon. Most are beautifully simple:

• Dhuhr is solar noon — when the sun is at its highest point
• Asr begins when a shadow equals the length of an object
• Maghrib is sunset — the moment the sun dips below the horizon

These three are precise to the minute anywhere in the world. The disagreement doesn't live here.

Fajr and Isha are the problem children. Both are tied to twilight — the period when the sky is neither fully dark nor fully lit. Fajr begins at astronomical dawn, when the sun is below the horizon but its light just barely reaches the upper atmosphere. Isha ends when that last twilight disappears completely.

The Arabic word ghasaq — the darkness of night — is precisely what astronomers call the end of astronomical twilight. The verse is describing a real, measurable celestial event.

The angle question

Twilight is defined by how far below the horizon the sun sits. When the sun is exactly 0°, it's on the horizon — that's sunset or sunrise. As it drops further below, the sky darkens progressively.

Astronomers define three stages of twilight:

• Civil twilight ends at 6° below the horizon
• Nautical twilight ends at 12° below
• Astronomical twilight ends at 18° below — the point when the sky is truly dark

For prayer purposes, Islamic scholars have studied which angle corresponds to the beginning of Fajr (true dawn) and the end of Isha (disappearance of twilight). And this is where the disagreement lives.

Different organisations, after decades of observation, have settled on different angles:

| Method | Fajr angle | Isha angle | |--------|------------|------------| | MUIS (Singapore) | 20° | 18° | | Muslim World League | 18° | 17° | | ISNA (North America) | 15° | 15° | | Egyptian Authority | 19.5° | 17.5° |

A 1° difference in the Fajr angle shifts the prayer time by 4–6 minutes. A 3° difference — the spread between MUIS and ISNA — shifts it by up to 18 minutes. That's not a rounding error. That's nearly an entire prayer window for someone setting their alarm.

Why MUIS uses 20° for Fajr

Singapore sits close to the equator, between 1° and 1.5° north latitude. At this latitude, the sky behaves differently from London or Istanbul. The angle of the sun's path relative to the horizon is steeper, which means twilight transitions faster.

MUIS arrived at the 20° Fajr angle through careful observation calibrated to Singapore's atmospheric and geographic conditions. The same process was done by local religious authorities across the Muslim world, which is why different countries have legitimately different standards.

Why apps give different answers

When an app lets you select a calculation method, it's asking you to choose which angle to use for Fajr and Isha. Apps that default to ISNA (built for a North American audience) will give you a noticeably later Fajr than MUIS — the sky is still partially lit when their "dawn" begins.

The confusion is compounded by apps that claim to auto-detect your location but don't auto-select the correct method for that location. They might place you correctly in Singapore but calculate using MWL, which gives a different result from the official MUIS timetable.

What about Asr? Isn't there disagreement there too?

Yes — though it's simpler. The Shafi'i, Maliki, and Hanbali schools define Asr as beginning when an object's shadow equals its own length. The Hanafi school uses double the object's length. In Singapore, this creates a roughly 30–60 minute difference between the two, depending on the season.

MUIS follows the majority Shafi'i ruling for the Asr start time, which aligns with most mosques in Singapore.

The practical conclusion

If you're praying in Singapore:

1. Use the official MUIS timetable. You can check it directly at the MUIS website, or use our Prayer Times tool which uses the verified MUIS 2026 timetable, accurate to the minute.

2. If an app asks you to "select a calculation method," choose MUIS — not MWL, not ISNA.

3. For Asr, use the Shafi'i ruling unless you follow the Hanafi madhab.

The 12-minute gap you see between apps isn't anyone being careless. It's centuries of astronomical observation and jurisprudential reasoning, compressed into a dropdown menu. The right choice for Singapore has already been made by scholars who studied our sky. Use their answer.