UK Ramadan fasting times for last year (2016)

Bismillah. As I’ve written about before, there are different views on excessive fasting hours in the summer at high latitudes such as the UK. I am not going to repeat those, but try to provide the scientific, astronomical data, information and knowledge to help support others to come to their own conclusions.

In the first of these posts, I am including the dawn, sunset & possible fasting times from last year (2016) because then, mid-Ramadan coincided with mid-summer, hence giving the longest average fasting lengths in the 33-year cycle as the lunar years move through solar years.

Examples of dawn/sunset timings for the UK, 2016
(four UK capital cities)

This data is taken from HMNAO’s Websurf 2.0 website, and was reproduced with permission by the ASCL in their Ramadan 2016 guidelines. I have used the four UK capital cities, with three dates for each, roughly corresponding to: beginning, middle & end of Ramadan.

Date City Dawn (AST) Dawn (15D) Dawn (NAUT) Sunrise Sunset Fasting length (AST) Fasting length (15D) Fasting length (NAUT)
07 June London *** 0147 0248 0445 2114 *** 19:27 18:26
22 June (midsummer)   *** 0117 0241 0443 2122 *** 20:05 18:41
06 July   *** 0156 0256 0452 2118 *** 19:22 18:22
07 June Ed’burgh *** *** *** 0429 2154 *** *** ***
22 June (midsummer)   *** *** *** 0427 2203 *** *** ***
06 July   *** *** *** 0437 2158 *** *** ***
07 June Cardiff *** 0159 0300 0457 2126 *** 19:27 18:26
22 June (midsummer)   *** 0131 0254 0456 2134 *** 20:03 18:40
06 July   *** 0209 0308 0504 2130 *** 19:21 18:22
07 June Belfast *** *** 0209 0450 2156 *** *** 19:47
22 June (midsummer)   *** *** *** 0447 2204 *** *** ***
06 July   *** *** 0219 0457 2200 *** *** 19:41


AST refers to astronomical twilight, when begins or ends when the sun is 18 degrees below the horizon

15D refers to when the sun is 15 degrees below the horizon

NAUT refers to nautical twilight, when begins or ends when the sun is 12 degrees below the horizon

The astronomical definition of “dawn” is disputed, with various Muslim religious authorities adopting one of the three possible definitions given above.

*** in the above table means that the timing is not available, because the sun does not reach that far below the horizon. This happens every year during the summer at high latitudes, such as the UK.



  1. As confirmed by HMNAO, there is always a possible error of 1-2 minutes in sunrise and sunset timings: although we can calculate exactly the position of the sun relative to our horizons, refraction of the sun’s rays can introduce an error: the sun may be below the horizon but we see it just above, due to refraction.  (This does not always happen, of course: hence the error will be zero, one or two minutes.) This means that technically, mosque prayer timetables may wish to add 2 minutes to sunset timings and subtract 2 minutes from sunrise timings, just to be safe about the timings of the sunset and dawn prayers, and for breaking the fast.  However, this might also be hair-splitting: I recommend making these adjustments, but would not worry if they are not made.
  2. If we use astronomical twilight (Sun’s depression = 18 degrees) as the start of dawn, this did not occur at all during Ramadan 2016 in any of the four capital cities. Therefore, the fasting start time and fasting length were undefined.
  3. If we use (Sun’s depression = 15 degrees) as the start of dawn, this did not occur at all during Ramadan 2017 in Edinburgh or Belfast. Therefore, the fasting start time and fasting length were undefined in those cities. However, it did occur in London and Cardiff, giving fasting lengths of 19.5-20 hours during the month.
  4. If we use nautical twilight (Sun’s depression = 12 degrees) as the start of dawn, this resulted in fasting hours during Ramadan 2016 in London and Cardiff of ~18.5 hours, and in Belfast of just under 20 hours at the beginning and end of Ramadan, but not in mid-Ramadan (mid-summer). We had no defined fasting hours throughout Ramadan 2016 for Edinburgh.
  5. Hence, it should be obvious that some ijtihad is required, eg a fraction of the night or a lower angle of the Sun below the horizon to designate the “beginning” of dawn.

NB: Our local latitude determines the lowest angle the Sun will dip below the horizon at mid-summer (~22 June). This angle can easily be calculated by subtracting 66.5 degrees (the latitude of the Arctic & Antarctic Circles) from the local latitude.


Within the Arctic Circle (66.5 deg or higher latitude), lowest Sun angle = zero or higher: the sun doesn’t set at all in the “land of the midnight sun.”

Edinburgh (56.0 deg lat): lowest Sun angle at midsummer = 56.0 – 66.5 = 10.5 deg below the horizon

Belfast (54.6 deg lat): lowest Sun angle at midsummer = 54.6 – 66.5 = 11.9 deg below the horizon

London & Cardiff (both 51.5 deg lat): lowest Sun angle at midsummer = 51.5 – 66.5 = 15 deg below the horizon

*NB: even using these angles of 10.5 deg, ~12 deg, 15 deg & 15 deg for Edinburgh, Belfast, London & Cardiff respectively will give very long fasting hours, as the table of timings above demonstrates.

Btw for Paris (48.9 deg lat): lowest Sun angle at midsummer = 48.9 – 66.5 = 17.6 deg below the horizon, so using the 18-degree rule gave no timings for Paris or anywhere north of it either, at midsummer.

Usama Hasan, Fellow of the Royal Astronomical Society, UK


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