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<div class="moz-cite-prefix">On 5/31/20 6:25 PM, Matt Johnson-Pint
wrote:<br>
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Forgive me if this is in any way ignorant, but why must the DST
transitions align so precisely with Ramadan? </div>
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Because, during the Ramadan, the Muslims don't eat/drink from the
sunrise to the sundown, so in Morocco with a GMT+1 timezone, the
first lunch of the day will be near 08:30 pm (named 'Ftour' -
Breakfast). So the people (and government) prefer switch back to
GMT+0 to have the first lunch earlier during this month.<br>
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<div style="color: rgb(33, 33, 33); background-color: rgb(255,
255, 255); text-align: left;" dir="auto">Would it not be
sufficient if the dates for the time change were predictable as
long as the switch to GMT occurred sometime before the start of
Ramadan and the switch back to GMT+1 occurred sometime after?
Is there a political, social, or religious reason why they must
be so exactly aligned?</div>
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-Matt</div>
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<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt"
face="Calibri, sans-serif" color="#000000"><b>From:</b> tz
<a class="moz-txt-link-rfc2396E" href="mailto:tz-bounces@iana.org"><tz-bounces@iana.org></a> on behalf of Milamber
<a class="moz-txt-link-rfc2396E" href="mailto:milamberspace@gmail.com"><milamberspace@gmail.com></a><br>
<b>Sent:</b> Sunday, May 31, 2020 7:03:50 AM<br>
<b>To:</b> Florian Weimer <a class="moz-txt-link-rfc2396E" href="mailto:fw@deneb.enyo.de"><fw@deneb.enyo.de></a>; Paul
Eggert <a class="moz-txt-link-rfc2396E" href="mailto:eggert@cs.ucla.edu"><eggert@cs.ucla.edu></a><br>
<b>Cc:</b> Time zone mailing list <a class="moz-txt-link-rfc2396E" href="mailto:tz@iana.org"><tz@iana.org></a><br>
<b>Subject:</b> Re: [tz] FW: [Ext] The TZ Coordination</font>
<div> </div>
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<div class="x_moz-cite-prefix">On 5/31/20 12:09 PM, Florian
Weimer wrote:<br>
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<pre>* Paul Eggert:
</pre>
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<pre>On 5/30/20 7:00 AM, Florian Weimer wrote:
</pre>
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<pre>Would this be a good opportunity to engage with the government of Morocco
to encourage them to give more warning?
</pre>
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<pre>My understanding is that at present, they don't know themselves in
advance.
</pre>
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<pre>Yes, I think you're right.
</pre>
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<pre>They would have to redefine the criteria to something based
exclusively on astronomical calculations
</pre>
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<pre>That shouldn't be necessary, as they're using a conservative
approximation; that is, it's OK if their approximation is a bit off
because all they need to do is to bracket the actual Ramadan rather
than predict its Gregorian dates exactly. If they had an algorithm
they could publish it and we could use it. And it would be
technically feasible for them to have an algorithm; see the
Morocco-prediction code in the tzdb 'africa' file for an example
algorithm.
</pre>
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<pre>It looks like the algorithm predicted correctly the data of Eid
al-Fitr as 24 May, but the derivation of the end date from that is
suspicious. I think it would make more sense if the time change does
not happen on Eid itself. </pre>
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<br>
In Morocco (where I live), the end of Ramadan (arabic month) is
follow by the Eid al-Fitr, and concretely it's 1 or 2 day off
for the people (with traditional visiting of family, big
lunches/diners, etc.). So for this year the astronomical
calculations don't include the following 2 day off in the calc.
This 2 days have fall in a Sunday/Monday, so it's not acceptable
by people to have a time shift during these 2 day off.<br>
<br>
Perhaps, you can modify the (predict) rules for next years : if
the end of Ramadan is a (probable) Friday or Saturday (and so
the 2 day off is on a weekend), the next time shift will be the
next weekend.<br>
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<pre> A rule like this would ensure that Eid
still uses the same time as Ramadan in every year, which is likely
what people expect.
</pre>
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