From: Dan Abitbol dabitbol at streamwide.com Thu Mar 15 10:21:07 UTC 2012 Hello Sorry to disturb again but as you know Morocco have new DST rules and first change is scheduled on 25 March 15, 2012-03-15 Do you plan to release 2012c that takes into account these new rules for Morocco soon ? .............. Reply: This is not going to be easy. If I understand the rules correctly, then the clocks will be put back during the month of Ramadan. Since the Islamic calendar wanders through the Gregorian calendar, in some years the full month of Ramadan falls in the summertime period, in some years Ramadan falls in the wintertime period and in other years the month of Ramadan partially overlaps with the DST period. I made a table for a couple of forthcoming years. Please note that this table is useless! The beginning of an Islamic month starts as soon as a religious authority declares that the crescent of the moon, immediately after an astronomical new moon, has been observed. This can't be predicted, but it can be approximated by some algorithm. For the table I have used the algorithm for the arithmetical Islamic calendar from Reingold in Calendrical Calculations 2. Note that an Islamic day actually starts at sunset of the day before the day mentioned. Table. (Best viewed with a monospace font). Column 1: Islamic year count. Column 2: the last Sunday of March in the Gregorian calendar. Column 3: the last Sunday of September in the Gregorian calendar. Column 4: the first day of the islamic month Ramadan in the Gregorian calendar. Column 5: the last day of the islamic month Ramadan in the Gregorian calendar. Islamic last Sun. last Sun. first of last of year March Sept. Ramadan Ramadan Gregorian Gregorian 1433 2012-3-25 2012-9-30 2012-7-20 2012-8-18 1434 2013-3-31 2013-9-29 2013-7-9 2013-8-7 1435 2014-3-30 2014-9-28 2014-6-29 2014-7-28 1436 2015-3-29 2015-9-27 2015-6-18 2015-7-17 1437 2016-3-27 2016-9-25 2016-6-7 2016-7-6 1438 2017-3-26 2017-9-24 2017-5-27 2017-6-25 1439 2018-3-25 2018-9-30 2018-5-16 2018-6-14 1440 2019-3-31 2019-9-29 2019-5-6 2019-6-4 1441 2020-3-29 2020-9-27 2020-4-24 2020-5-23 1442 2021-3-28 2021-9-26 2021-4-13 2021-5-12 1443 2022-3-27 2022-9-25 2022-4-3 2022-5-2 1444 2023-3-26 2023-9-24 2023-3-23 2023-4-21 1445 2024-3-31 2024-9-29 2024-3-11 2024-4-9 1446 2025-3-30 2025-9-28 2025-3-1 2025-3-30 1447 2026-3-29 2026-9-27 2026-2-18 2026-3-19 1448 2027-3-28 2027-9-26 2027-2-8 2027-3-9 1449 2028-3-26 2028-9-24 2028-1-28 2028-2-26 1450 2029-3-25 2029-9-30 2029-1-16 2029-2-14 1451 2030-3-31 2030-9-29 2030-1-6 2030-2-4 1452 2031-3-30 2031-9-28 2030-12-26 2031-1-24 1453 2032-3-28 2032-9-26 2031-12-15 2032-1-13
From the table you can see that, for instance, in the Gregorian year 2012 the month Ramadan completely falls in the summertime period. In the Gregorian year 2026 the full month Ramadan falls outside the summertime period. In the Gregorian year 2023 Moroccan summertime starts effectively April 21 plus one (this is 1 Shawwal) (give or take 2 days; see above why), since Ramadan started just before the last Sunday of March. That's my interpretation, which can differ from the official one!
Oscar van Vlijmen