Why Do Prayer Times Differ? Cities, Methods and Twilight Angles

Two calendars can show different Fajr times for the same city on the same day, sometimes a couple of minutes apart, sometimes half an hour. This is not a mistake. Prayer times are not observed but calculated from the position of the sun relative to the horizon, and at several steps of that calculation different authorities use different values. Here is exactly where the difference comes from.

Geography first: times differ from city to city

Prayer times depend on the position of the sun at your exact point, so every city has its own. Longitude translates directly into clock time: moving one degree east makes the sun rise about four minutes earlier. Istanbul and Van are about fourteen degrees apart in longitude, which alone is more than an hour. Latitude amplifies the seasonal swing: the further north you go, the shorter summer nights become and the closer Fajr and Isha move to each other. There is no single national timetable; each city has its own.

The main difference: Fajr and Isha angles

Fajr and Isha are defined by how many degrees the sun sits below the horizon. There is no consensus on that angle, and each authority uses its own. Common values are: Diyanet and the Muslim World League use 18 degrees for Fajr and 17 for Isha; the University of Islamic Sciences in Karachi uses 18 and 18; the Egyptian General Authority of Survey 19.5 and 17.5; the Islamic Society of North America (ISNA) 15 and 15; Singapore/MUIS 20 and 18; Umm al-Qura 18.5 degrees for Fajr. One degree corresponds to roughly four to eight minutes depending on season and latitude. The gap between ISNA's 15 degrees and Singapore's 20 can reach half an hour in summer.

Asr: the shadow ratio

Asr begins when an object's shadow reaches a certain ratio of its height. In the Shafi'i, Maliki and Hanbali understanding this is when the shadow equals the object's length; in the Hanafi understanding it is when the shadow reaches twice that length. Depending on the season this creates a difference of twenty to sixty minutes, and it explains why two calendars can diverge so widely for Asr. Both calculations are internally consistent; which one you follow depends on the position you adhere to.

Isha: an angle, or a fixed interval?

Some authorities define Isha not by an angle but by a fixed interval after Maghrib. In the Umm al-Qura and Qatar calendars Isha falls ninety minutes after Maghrib, and a hundred and twenty minutes during Ramadan. Because a fixed interval gives the same gap every day of the year, it diverges noticeably from the angle method, especially in summer and winter.

Precaution: some of the minutes are a safety margin

The calculation gives the mathematical moment a time begins. Many authorities add a margin of precaution: Fajr is moved a few minutes earlier and Maghrib a few minutes later. The purpose is to make certain the time has genuinely entered despite altitude, atmospheric conditions and uncertainty about the visible horizon. This is why a raw calculation and an official timetable usually differ by a minute or two.

High latitudes: where the sun does not set far enough

Beyond roughly the forty-eighth parallel, the sun never descends eighteen degrees below the horizon during summer. On such days Fajr and Isha simply do not occur mathematically. Methods such as dividing the night into portions, using the nearest normal day, or applying a fixed proportion are used instead. This is why differences are large in summer in cities like Stockholm, Helsinki, London and Berlin.

Which one is correct?

None of the methods is wrong; they are the same astronomical calculation applied with different assumptions. In practice the soundest approach is to follow the timetable of the official religious authority of the country you are in, and, if you pray in congregation, the times of your local mosque. When sources differ by a few minutes, choosing the cautious side — earlier for Fajr, later for Maghrib — is a safe habit.

Which method does QiblaTap use?

For each city we apply the method commonly accepted in that country: Diyanet in Türkiye, Umm al-Qura in Saudi Arabia and the Gulf states, the Egyptian General Authority of Survey in Egypt, Karachi in Pakistan, India and Bangladesh, Kemenag in Indonesia and JAKIM in Malaysia, ISNA in North America, and the Muslim World League elsewhere. For cities beyond the forty-eighth parallel a high-latitude rule is applied automatically. Every prayer times page states which method was used, so you always know where the times you see come from.