I just came across a note about Morocco, which entered daylight savings time in March 2016, but then left daylight-savings in June for 35 days, re-starting daylight-savings in July [1].
I've read that the explanation for this temporary suspension of daylight-savings is Ramadan [2], and Ramadan is dependent on the observed sighting of the new moon - so you can't necessarily predict the date in advance.
I ended up coming across that after looking for an explanation for something bizarre I experienced on a trip to Morocco in March 2016…with my iPhone set to use "Marrakesh, Morocco", the time on the phone displayed correctly, but the time on my sync'd Apple watch was an hour out. I think I ended up manually setting it to Paris time to get the correct time, but never did get an explanation for the difference.
So even across two devices from the same manufacturer, theoretically sharing the same date-time information, they can be inconsistent.
I've read that the explanation for this temporary suspension of daylight-savings is Ramadan [2], and Ramadan is dependent on the observed sighting of the new moon - so you can't necessarily predict the date in advance.
I ended up coming across that after looking for an explanation for something bizarre I experienced on a trip to Morocco in March 2016…with my iPhone set to use "Marrakesh, Morocco", the time on the phone displayed correctly, but the time on my sync'd Apple watch was an hour out. I think I ended up manually setting it to Paris time to get the correct time, but never did get an explanation for the difference.
So even across two devices from the same manufacturer, theoretically sharing the same date-time information, they can be inconsistent.
Conclusion: time is hard!
[1] https://www.timeanddate.com/time/change/morocco/tanger?year=...
[2] http://codeofmatt.com/2016/04/23/on-the-timing-of-time-zone-...