How prayer times are calculated and why they differ
Understand how location, time zones, calculation methods, Asr conventions and twilight affect prayer times, and how to compare settings with your mosque timetable.
Start with the location
Prayer times depend on latitude and longitude. Two cities can share a country and time zone but have different prayer times. City pages use a specified point near the centre. If you are some distance away, open Salati and select your own city or actual location. Reading a city timetable does not require location permission.
Local clocks and daylight saving
Astronomical calculations must be converted to the city’s local clock. Salati uses the city’s time zone, including daylight-saving transitions where applicable. The city can reach a new date before or after the device you are using, so the timetable follows the city’s local calendar date.
Why Fajr and Isha differ
Many conventions use the sun’s angle below the horizon to estimate twilight. Authorities use different angles, while some conventions determine Isha with a fixed interval after Maghrib. Umm al-Qura and Qatar are interval-based examples in the engine, with the Ramadan interval applied for Umm al-Qura. A method change can shift Fajr and Isha even when the clock is correct.
Asr conventions
The app supports Shafi and Hanafi Asr calculations. They use different shadow lengths to identify the start, so Hanafi Asr is usually later. Each city page identifies its convention. You can change the app setting to match the convention used by your congregation.
High latitudes
In a city such as London, summer twilight can persist and a chosen solar angle may not occur on some nights. The engine applies a high-latitude rule, while mosques may use different rules or published timetables. Compare with a local authority, especially for Fajr and Isha in summer.
Calculated and stored timetables
The source line identifies whether the displayed day comes from a regional calculation or a stored calendar within its coverage. Muscat has stored coverage for October 2026; outside that coverage the regional calculation is used. A calculated timetable is not necessarily an approved copy of every mosque’s schedule, and it does not set iqamah times.
Choosing your settings
First select the correct city and time zone, then the calculation method and Asr convention used locally. Compare several prayers on more than one day with a local authority’s timetable rather than adjusting every prayer from one observation. The app saves minute adjustments you choose, but the city directory’s timetables are independent of your personal preferences.
Reading the weekly table
The table covers seven consecutive dates in the city’s local time. Sunrise is included for reference and is not an obligatory prayer. Dates refresh when the page opens with JavaScript enabled. Without JavaScript, check the displayed snapshot date and warning before relying on the timetable.
Further reference: Calculation method definitions