I'm forwarding this message from Michael Deckers, who is not on the time zone mailing list. Those of you who are on the list, please direct replies appropriately. --ado ________________________________________ From: Michael Deckers [michael.deckers@yahoo.com] Sent: Friday, July 23, 2010 4:54 PM To: Olson, Arthur David (NIH/NCI) [E] Subject: Re: FW: Egypt plan to [cancel] DST during Ramadan and then to resume DST again. On 2010-07-22 20:01, Arthur David Olson wrote:

I'm forwarding this message from Michael Deckers, who is not on the time zone mailing list. Those of you who are on the list, please direct replies appropriately.

Thank you!

(Both... http://www.worldtimezone.com/dst_news/dst_news_egypt02.html ...and... http://www.almasryalyoum.com/en/news/clocks-go-back-during-ramadan-and-then-... ...indicate that clocks are "...to be moved forward again after Ramadan, on Thursday 9 September.")

Right. In the first case, you have interpreted "midnight on Tuesday 10 August" as 2010-08-10 + 24 h, with the switch of local time to 2010-08-10 + 23 h, in the second case, you have interpreted "on Thursday 9 September" as 2010-09-09 + 00 h, rather than as 2010-09-09 + 24 h with the switch of local time to 2010-09-09 + 25 h. This is inconsistent and, in my opinion, differs from the intended meaning of the source(s). It is certain that Ramadan will end only on the eve of 2010-09-09 in Egypt. Of course, one might say this is just one hour over one day. But for historical accuracy, other evidence (such as local reporting and air traffic schedules) should be considered before the matter is decided to the nearest minute. The tz database is really a great resource, but it lacks a systematic method to designate the uncertainty of its data (besides the comments). Regards Michael Deckers.