Many Masājid in the UK use the same timetable for Ṣalāh every year. Is this correct?
بسم اللہ الرحمن الرحیم
This is incorrect. Masājid should ensure that the Ṣalāh timetable is reviewed and updated every year.
The Gregorian calendar we use begins in January and ends in December. It is a solar based calendar that reflects the time it takes the Earth to make one complete orbit around the sun. It is for this reason, the summer and winter months occur in the same months every year unlike the Islamic calendar which is based on the lunar cycle.
A normal year in the Gregorian is defined as 365 days. However, the exact time it takes for the Earth to orbit the sun is 365.242199 days. For this reason, every four years, the Gregorian calendar has a leap year containing one additional day in order to keep the calendar year synchronised with the astronomical year.
It is therefore incorrect to use the same calendar for Ṣalāh every year. This is because the Ṣalāh times are solar based and the times will differ every year based on the fact that 365 days or 366 days is not the exact time it takes for the Earth to orbit around the sun. The following two examples illustrate this point.
Sunrise and sunset times in Blackburn BB1 6LS
1 March 2011 – 06.59 and 17.47
1 March 2012 – 06.57 and 17.48
1 March 2013 – 06.58 and 17.47
1 March 2014 – 06.58 and 17.47
1 March 2015 – 06.59 and 17.47
Astronomical twilight (18 degrees) in Blackburn BB1 6LS
12 May 2011 – 01.34
12 May 2012 – 01.20
12 May 2013 – 01.26
12 May 2014 – 01.30
12 May 2015 – 01.34
Allah knows best
16 Jumādā al-Thāniyah 1436 / 5 April 2015