Fajr
Begins when the sun reaches a specific angle below the eastern horizon (typically between 15° and 19.5°, depending on the method) — the moment the first true dawn light appears just before sunrise.
A detailed explanation of how prayer times are calculated astronomically in Riyadh, including the available calculation methods and how they differ.
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Prayer times in Riyadh are calculated using precise astronomical calculations based on the position of the sun, Riyadh's geographical coordinates, the selected calculation method, and the Islamic juristic school.
Prayer times are never fixed or arbitrary — they are derived from the sun's actual angle relative to Riyadh's horizon at every moment, using well-established astronomical formulas that account for latitude, longitude, and time zone.
This site bases its calculations on the Umm al-Qura calendar, the official method used in Saudi Arabia, while also offering other internationally recognized calculation methods.
This page explains in detail the astronomical basis of each prayer, the main calculation methods available, and why some apps show slightly different times for the same location.
The Earth orbits the sun in an elliptical path while tilted on its axis at a fixed angle, which makes the angle of sunlight falling on Riyadh shift gradually every day throughout the year.
This constant shift causes sunrise and sunset to move slightly earlier or later each day, and with them every prayer time tied to them — even if the difference is just a single minute.
This daily change is natural and astronomically expected — it is the same reason prayer times differ more noticeably between summer and winter in Riyadh. Hijri Date
Each of the five obligatory prayers has a precise astronomical moment that marks the start of its time. Below is the basis on which each one is calculated.
A simplified diagram showing the sun's approximate position relative to the horizon at the start of each prayer time.
Begins when the sun reaches a specific angle below the eastern horizon (typically between 15° and 19.5°, depending on the method) — the moment the first true dawn light appears just before sunrise.
The moment the sun's upper edge appears above the eastern horizon — used as an astronomical reference marking the end of Fajr time and the start of certain voluntary prayers.
Begins when the sun reaches its highest point in the sky for Riyadh's location (solar noon) — the moment any object's shadow is at its shortest.
Begins when an object's shadow length equals its own length (per the majority of schools) or twice its length (per the Hanafi school), added to the shadow length at Dhuhr.
Begins the instant the sun's disc fully sets below the western horizon — one of the prayer times with the most agreement across calculation methods.
Begins when the red twilight fully disappears from the western horizon, typically calculated at an angle between 15° and 18° below the horizon, or as a fixed time offset after Maghrib, as in the Umm al-Qura method.
Every prayer-time calculation method relies on four core astronomical and geographical elements.
The sun's exact position (its declination and altitude) is calculated moment by moment using standard astronomical formulas — the foundation from which every prayer time is derived.
Every prayer except Dhuhr and Maghrib is tied to a specific angle of the sun above or below the horizon; the larger the angle used, the earlier Fajr begins and the later Isha begins.
Riyadh's precise geographic coordinates determine the exact moment the sun reaches each angle, and this factor matters more the farther a location is from the equator. (24.7136°, 46.6753°)
The calculated astronomical times are converted into Riyadh's local time (Asia/Riyadh, UTC+3) so they can be used directly by worshippers.
The difference in the sun's angle between summer and winter creates noticeable shifts, especially in Fajr and Isha times, as shown in the table below.
| Summer | Winter | |
|---|---|---|
| Approximate Fajr time | About 3:30 AM | About 5:45 AM |
| Approximate Isha time | About 9:00 PM | About 6:30 PM |
| Day length | Over 13 hours | Under 11 hours |
| Gap between Maghrib and Isha | Relatively shorter | Relatively longer |
Each method uses a different pair of angles to determine Fajr and Isha, which explains the slight differences between various apps and websites.
| Calculation Method | Fajr Angle | Isha Angle | Region |
|---|---|---|---|
| Umm al-Qura University, Makkah | 18.5° | 90 minutes after Maghrib | Saudi Arabia (official method) |
| Muslim World League | 18° | 17° | Europe and large parts of Asia and Africa |
| Egyptian General Authority of Survey | 19.5° | 17.5° | Egypt, Syria, Lebanon, Iraq, and parts of Africa |
| University of Islamic Sciences, Karachi | 18° | 18° | Pakistan, Afghanistan, Bangladesh, and India |
| Islamic Society of North America (ISNA) | 15° | 15° | North America |
| Gulf Region | 19.5° | 90 minutes after Maghrib | Arab Gulf countries |
Saudi Arabia officially follows the "Umm al-Qura University" method because it is the government-adopted standard for all civil, religious, and official purposes in the Kingdom — and it is the default method on this site to keep Riyadh's times aligned with the official reference.
All juristic schools agree on the times of Fajr, Dhuhr, Maghrib, and Isha — the only real disagreement is over when Asr begins.
The majority of scholars (Shafi'i, Maliki, and Hanbali) hold that Asr begins when an object's shadow equals its length, while the Hanafi school holds that it begins when the shadow reaches twice the object's length — making Hanafi Asr typically 30 to 45 minutes later than the other schools.
| Juristic School | Shadow Ratio | Resulting Asr Time |
|---|---|---|
| Shafi'i | Shadow length = object length (1×) | Relatively earlier Asr time |
| Maliki | Shadow length = object length (1×) | Relatively earlier Asr time |
| Hanbali | Shadow length = object length (1×) | Relatively earlier Asr time |
| Hanafi | Shadow length = twice the object length (2×) | Asr delayed by about 30-45 minutes |
Early Muslims relied on simple tools such as measuring shadow length with a vertical gnomon (sundial), watching the threads of dawn and twilight directly with the naked eye, and observing star positions to estimate time at night.
The modern method relies on precise astronomical formulas, GPS coordinates, and systems that generate times automatically via APIs — offering far greater accuracy and consistency unaffected by weather conditions or direct visibility.
Prayer-time calculation in Saudi Arabia, and specifically on this site, draws on a combination of the following bodies and sources.
If you notice a difference between this site and another app, the cause is usually one of the following reasons — not an error in either one.
Why is my local mosque's adhan 2 minutes different from this site?
Some mosques add a small manual safety margin (usually one or two minutes) before Fajr or after Maghrib to make sure the time has genuinely begun before the call to prayer — this doesn't mean either calculation is wrong.
Why do different apps show different prayer times for Riyadh?
This is usually due to differing default calculation methods or juristic schools between apps, not an error in the underlying astronomical data.
Why do prayer times change every day even though I haven't changed any settings?
This is natural and astronomically expected — the sun's position relative to Riyadh shifts daily because of Earth's orbit and axial tilt, causing small daily changes in every prayer time.
Prayer times are calculated astronomically by determining the sun's angle relative to the horizon at a given location (latitude and longitude), then converting those astronomical moments into local time.
Because the angle of sunlight falling on Riyadh changes daily as a result of Earth's orbit and axial tilt, producing small, predictable shifts in every prayer time.
This site defaults to the Umm al-Qura University method, the official method used in Saudi Arabia, though it can be changed from the settings.
It is an astronomical calculation method that uses an 18.5° angle for Fajr and a fixed 90-minute offset after Maghrib for Isha, and it is the officially adopted method in Saudi Arabia.
Because it is the official government-adopted method for all civil and religious purposes in the Kingdom, ensuring consistent announced times across all mosques and official institutions.
The Shafi'i school (along with Maliki and Hanbali) holds that Asr begins when the shadow equals the object's length, while the Hanafi school holds it begins when the shadow reaches twice the object's length — making Hanafi Asr about 30-45 minutes later.
The most common cause is a different default juristic school (Shafi'i or Hanafi) in each app, not an error in the astronomical calculation itself.
It is the angle the sun must reach below the eastern horizon for Fajr to begin, typically ranging between 15° and 19.5° depending on the calculation method used.
It is the angle the sun must reach below the western horizon for Isha to begin, typically ranging between 15° and 18°, or calculated as a fixed time offset after Maghrib in some methods.
Because the twilight angle in the Hijaz region is difficult to observe astronomically with consistent precision during certain times of the year, so Umm al-Qura adopted a fixed 90-minute offset after Maghrib as a more stable practical solution.
Dhuhr begins when the sun reaches its highest point in the sky for Riyadh's location (solar noon) — the moment any object's shadow is at its shortest for the day.
Maghrib begins the instant the sun's disc fully sets below the western horizon — one of the times with the strongest agreement across calculation methods, since the moment of sunset is astronomically unambiguous.
Because Dhuhr depends on a single precisely defined astronomical moment (solar noon), while Fajr and Isha depend on twilight angles that can be estimated in several different ways, leaving more room for variation between them.
Yes — modern astronomical calculations are highly accurate and based on fixed scientific formulas, making them more consistent than traditional methods that relied on direct observation and weather conditions.
The traditional method relied on simple tools such as a shadow-measuring stick and observing twilight with the naked eye, while modern calculation relies on precise astronomical formulas, GPS coordinates, and automated APIs.
This site relies on Aladhan API, a trusted service that provides accurate prayer-time calculations across different methods, including the official Umm al-Qura method.
Yes, you can choose the calculation method and juristic school that suit you from the homepage settings, and every displayed time will update instantly.
Some mosques apply a small manual safety margin (one or two minutes) to make sure the time has genuinely begun before the call to prayer is raised — this is a common, natural difference and not a sign of error.
Yes — every calculated astronomical moment is converted to local time based on the time zone (Asia/Riyadh, UTC+3) before being displayed on the site.
Geographic coordinates determine the exact moment the sun reaches the required angle for each prayer, and this factor matters more the farther a location is from the equator.
Yes, every region of the Kingdom officially uses the same Umm al-Qura method, but the actual displayed times differ based on each city's own coordinates.
Solar noon is the moment the sun crosses the meridian (its highest point in the sky) for a given location — the exact moment Dhuhr time begins.
Sunset is astronomically defined as the moment the sun's upper edge disappears completely below the western horizon.
You can visit the site's homepage to see today's live, automatically updated prayer times, along with the full monthly schedule.
The astronomical basis of the calculation doesn't change, but Suhoor and Iftar times in Ramadan specifically are directly tied to the daily Fajr and Maghrib times, calculated the same way as usual.
Now that you understand the scientific basis behind the calculations, you can check today's live prayer schedule and customize the calculation method and juristic school that suit you.
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