Why one preset cannot match every UK mosque
In the United Kingdom, mosques and community bodies use several distinct approaches to compile daily prayer starts:
- Unified city schedules: In London, East London Mosque and many other mosques publish the London Unified Prayer Timetable (London Salah Times), a city-wide schedule compiled from local criteria rather than a single fixed depression angle.
- Mosque-specific timetables: Birmingham Central Mosque publishes its own monthly start and congregation schedule. Its winter Fajr start is about 14 minutes later than East London Mosque's, and its Maghrib start uses sunset without a three-minute precautionary addition.
- Algorithmic calculation methods: Prayer apps typically run a preset such as Moonsighting Committee Worldwide (SalahTable's UK default), Muslim World League (18° Fajr / 17° Isha) or ISNA (15° / 15°), combined with a high-latitude rule in summer when astronomical twilight never ends.
Because the published mosque timetables themselves differ by more than ten minutes on Fajr, no single calculation preset can agree within two minutes with every UK mosque simultaneously.
Dated winter comparisons: London and Birmingham (2026)
In our dated accuracy checks, we compared SalahTable's UK default (Moonsighting Committee Worldwide) day by day against the published start columns of East London Mosque (2026-11-01 to 2026-12-31, 61 days) and Birmingham Central Mosque (2026-11-01 to 2026-11-30, 30 days). Positive numbers mean SalahTable's calculated start is later than the mosque's published start.
| Prayer | London vs East London Mosque | Birmingham vs Birmingham Central Mosque | Why they differ |
|---|---|---|---|
| Fajr | +3.7 min (max 7 min, n=61) | -10.5 min (max 12 min, n=30) | Moonsighting sits between London Salah Times (earlier) and Birmingham Central Mosque (later) |
| Sunrise | +2.9 min (max 3 min, n=61) | +0.2 min (max 1 min, n=30) | Agrees within 1–3 minutes across sampled winter dates |
| Dhuhr | -0.1 min (max 1 min, n=61) | +0.2 min (max 1 min, n=30) | Agrees within 1–3 minutes across sampled winter dates |
| Asr (Hanafi) | -1.1 min (max 2 min, n=61) | -0.9 min (max 1 min, n=30) | Agrees within 1–3 minutes across sampled winter dates |
| Maghrib | -0.2 min (max 1 min, n=61) | +3.4 min (max 4 min, n=30) | Moonsighting and ELM include +3 min after sunset; Birmingham uses unadjusted sunset |
| Isha | -4.8 min (max 7 min, n=61) | -5 min (max 6 min, n=30) | Both mosques schedule winter Isha about 5 minutes later than Moonsighting general shafaq |
These figures compare prayer-start (“Begins”) columns, not congregation (jama‘ah / iqamah) times. They cover November and December 2026 only and do not measure summer agreement.
Three calculation presets across four seasons in 2027
To see how standard app settings diverge in the UK across the year, the table below compares Moonsighting Committee, Muslim World League (MWL, 18°/17° with seventh-of-the-night high-latitude fallback) and ISNA (15°/15°) in London and Birmingham on four dates in 2027.
| City / date | Moonsighting Fajr | MWL Fajr | ISNA Fajr | Moonsighting Isha | MWL Isha | ISNA Isha |
|---|---|---|---|---|---|---|
| London 21 March 2027 | 4:28 AM | 4:21 AM | 4:29 AM | 7:32 PM | 7:55 PM | 7:48 PM |
| London 21 June 2027 | 2:43 AM | 3:40 AM | 3:40 AM | 10:42 PM | 10:25 PM | 10:25 PM |
| London 21 September 2027 | 5:11 AM | 5:04 AM | 5:11 AM | 8:19 PM | 8:42 PM | 8:35 PM |
| London 21 December 2027 | 6:22 AM | 5:59 AM | 6:19 AM | 5:32 PM | 5:51 PM | 5:37 PM |
| Birmingham 21 March 2027 | 4:35 AM | 4:28 AM | 4:34 AM | 7:39 PM | 8:03 PM | 7:58 PM |
| Birmingham 21 June 2027 | 2:44 AM | 3:43 AM | 3:43 AM | 10:55 PM | 10:36 PM | 10:36 PM |
| Birmingham 21 September 2027 | 5:17 AM | 5:11 AM | 5:16 AM | 8:26 PM | 8:50 PM | 8:44 PM |
| Birmingham 21 December 2027 | 6:33 AM | 6:08 AM | 6:29 AM | 5:35 PM | 5:56 PM | 5:42 PM |
Summer persistence of twilight in Britain
Every UK city on SalahTable sits north of 50° N. From May through July, the sun never sinks 18° below the horizon at local midnight, and across much of Britain it also stays above 15° around the June solstice. Direct angle crossings for 18° Fajr and Isha therefore do not occur during those weeks; see our high-latitude prayer times dataset for exact city date ranges.
During that summer period, Moonsighting Committee switches to its latitude-based seasonal adjustment, while angle-based presets in Adhan apply a high-latitude rule (such as the seventh of the night). That is why two methods that both mention “18°” can produce very different May and June Fajr times in London, Manchester or Edinburgh.
How to choose your setting on UK city pages
- If you attend or follow a specific local mosque, use its published timetable for Fajr, Isha and congregation times.
- On any UK city page, use the method and Asr selector below today's times to switch between Moonsighting Committee, MWL, ISNA and other presets, and between Shafi‘i and Hanafi Asr.
- Remember that your browser saves the choice for all UK pages on this device, including monthly calendars.