[tz] 2014 DST changes in Egypt, again
Paul Eggert
eggert at cs.ucla.edu
Wed Jun 4 16:35:27 UTC 2014
Thanks for the heads-up. This most likely affects 2015 and later, too;
I've tried to come up with a pattern. Attached is a proposed patch,
which I've pushed into the experimental repository. Please give it a
try. We'll need another stable release soon.
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From 5e27c6a8eabb12d59b969e3631981b6228bd1fbb Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert at cs.ucla.edu>
Date: Wed, 4 Jun 2014 09:33:15 -0700
Subject: [PATCH] Egypt's Ramadan-based transitions expand to
Thursday-to-Thursday 24:00.
* africa (Egypt): 2014 transitions are June 26 and July 31 at 24:00.
(Thanks to Imed Chihi.) Guess a similar pattern for future years,
namely, DST is not observed in Ramadan, nor in the days following the
last Thursday before Ramadan, nor in the days preceding the first
Friday after Ramadan.
* NEWS: Document this.
---
NEWS | 6 +++++
africa | 85 ++++++++++++++++++++++++++++++++++++++++++++++--------------------
2 files changed, 65 insertions(+), 26 deletions(-)
diff --git a/NEWS b/NEWS
index dd0eee5..d16bd3b 100644
--- a/NEWS
+++ b/NEWS
@@ -2,6 +2,12 @@ News for the tz database
Unreleased, experimental changes
+ Changes affecting near-future time stamps
+
+ Egypt's 2014 Ramadan-based transitions are June 25 and July 31 at 24:00.
+ (Thanks to Imed Chihi.) Guess that transitions in future years
+ will follow a similar pattern.
+
Changes affecting past time stamps
The abbreviation "MSM" (Moscow Midsummer Time) is now used instead of
diff --git a/africa b/africa
index 83bff2e..628c086 100644
--- a/africa
+++ b/africa
@@ -342,46 +342,79 @@ Rule Egypt 2007 only - Sep Thu>=1 23:00s 0 -
# From Gunther Vermier (2015-05-13):
# our Egypt office confirms that the change will be at 15 May "midnight" (24:00)
-# From Paul Eggert (2014-05-13):
+# From Imed Chihi (2014-06-04):
+# We have finally "located" a precise official reference about the DST changes
+# in Egypt. The Ministers Cabinet decision is explained at
+# http://www.cabinet.gov.eg/Media/CabinetMeetingsDetails.aspx?id=347 ...
+# [T]his (Arabic) site is not accessible outside Egypt, but the page ...
+# translates into: "With regard to daylight saving time, it is scheduled to
+# take effect at exactly twelve o'clock this evening, Thursday, 15 MAY 2014,
+# to be suspended by twelve o'clock on the evening of Thursday, 26 JUN 2014,
+# and re-established again at the end of the month of Ramadan, at twelve
+# o'clock on the evening of Thursday, 31 JUL 2014." This statement has been
+# reproduced by other (more accessible) sites[, e.g.,]...
+# http://elgornal.net/news/news.aspx?id=4699258
+
+# From Paul Eggert (2014-06-04):
# Sarah El Deeb and Lee Keath of AP report that the Egyptian government says
# the change is because of blackouts in Cairo, even though Ahram Online (cited
-# above) says DST had no affect on electricity consumption. The AP story says
-# DST will not be observed during Ramadan. There is no information about when
-# DST will end. See:
+# above) says DST had no affect on electricity consumption. There is
+
+# no information about when DST will end this fall. See:
# http://abcnews.go.com/International/wireStory/el-sissi-pushes-egyptians-line-23614833
#
# For now, guess that later transitions will use 2010's rules, and that
# Egypt will agree with Morocco (see below) about the date Ramadan starts and
-# ends, though (unlike Morocco) it will switch at 00:00 standard time. In
-# Egypt the spring-forward transitions are removed for 2020-2022, when the
-# guessed spring-forward date falls during the estimated Ramadan, and all
-# transitions removed for 2023-2038, where the estimated Ramadan falls entirely
-# outside the guessed daylight-saving time. Ramadan intrudes on the guessed
-# DST starting in 2039, but that's beyond our somewhat-arbitrary cutoff.
-
+# ends, though (unlike Morocco) it will switch at 24:00 the last Thursday before
+# Ramadan, and at 00:00 the first Friday after Ramadan.
+# To estimate what the Egyptian government will do in future years,
+# transition dates for 2015 through 2037 were determined by running
+# the following program under GNU Emacs 24.3, with the results integrated
+# by hand into the table below. Ramadan again intrudes on the guessed
+# DST starting in 2038, but that's beyond our somewhat-arbitrary cutoff.
+# (let ((islamic-year 1436))
+# (while (< islamic-year 1460)
+# (let ((a (calendar-islamic-to-absolute (list 9 1 islamic-year)))
+# (b (calendar-islamic-to-absolute (list 10 1 islamic-year)))
+# (friday 5))
+# (while (/= friday (mod a 7))
+# (setq a (1- a)))
+# (while (/= friday (mod b 7))
+# (setq b (1+ b)))
+# (setq a (1- a))
+# (setq b (1- b))
+# (setq a (calendar-gregorian-from-absolute a))
+# (setq b (calendar-gregorian-from-absolute b))
+# (insert
+# (format
+# (concat "Rule\tEgypt\t%d\tonly\t-\t%s\t%2d\t24:00\t0\t-\n"
+# "Rule\tEgypt\t%d\tonly\t-\t%s\t%2d\t24:00\t1:00\tS\n")
+# (car (cdr (cdr a))) (calendar-month-name (car a) t) (car (cdr a))
+# (car (cdr (cdr b))) (calendar-month-name (car b) t) (car (cdr b)))))
+# (setq islamic-year (+ 1 islamic-year))))
Rule Egypt 2008 only - Aug lastThu 23:00s 0 -
Rule Egypt 2009 only - Aug 20 23:00s 0 -
Rule Egypt 2010 only - Aug 11 0:00 0 -
Rule Egypt 2010 only - Sep 10 0:00 1:00 S
Rule Egypt 2010 only - Sep lastThu 23:00s 0 -
Rule Egypt 2014 only - May 15 24:00 1:00 S
-Rule Egypt 2014 only - Jun 29 0:00s 0 -
-Rule Egypt 2014 only - Jul 29 0:00s 1:00 S
+Rule Egypt 2014 only - Jun 26 24:00 0 -
+Rule Egypt 2014 only - Jul 31 24:00 1:00 S
Rule Egypt 2014 max - Sep lastThu 23:00s 0 -
Rule Egypt 2015 2019 - Apr lastFri 0:00s 1:00 S
-Rule Egypt 2015 only - Jun 18 0:00s 0 -
-Rule Egypt 2015 only - Jul 18 0:00s 1:00 S
-Rule Egypt 2016 only - Jun 7 0:00s 0 -
-Rule Egypt 2016 only - Jul 7 0:00s 1:00 S
-Rule Egypt 2017 only - May 27 0:00s 0 -
-Rule Egypt 2017 only - Jun 26 0:00s 1:00 S
-Rule Egypt 2018 only - May 16 0:00s 0 -
-Rule Egypt 2018 only - Jun 15 0:00s 1:00 S
-Rule Egypt 2019 only - May 6 0:00s 0 -
-Rule Egypt 2019 only - Jun 5 0:00s 1:00 S
-Rule Egypt 2020 only - May 24 0:00s 1:00 S
-Rule Egypt 2021 only - May 13 0:00s 1:00 S
-Rule Egypt 2022 only - May 3 0:00s 1:00 S
+Rule Egypt 2015 only - Jun 11 24:00 0 -
+Rule Egypt 2015 only - Jul 23 24:00 1:00 S
+Rule Egypt 2016 only - Jun 2 24:00 0 -
+Rule Egypt 2016 only - Jul 7 24:00 1:00 S
+Rule Egypt 2017 only - May 25 24:00 0 -
+Rule Egypt 2017 only - Jun 29 24:00 1:00 S
+Rule Egypt 2018 only - May 10 24:00 0 -
+Rule Egypt 2018 only - Jun 14 24:00 1:00 S
+Rule Egypt 2019 only - May 2 24:00 0 -
+Rule Egypt 2019 only - Jun 6 24:00 1:00 S
+Rule Egypt 2020 only - May 28 24:00 1:00 S
+Rule Egypt 2021 only - May 13 24:00 1:00 S
+Rule Egypt 2022 only - May 5 24:00 1:00 S
Rule Egypt 2023 max - Apr lastFri 0:00s 1:00 S
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
--
1.9.1
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