From b724c2f69699a629a196fd997ea3c5b9fae6ab32 Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Tue, 15 Jul 2014 21:58:31 -0700
Subject: A few more changes for consistency.

* africa (Africa/Accra): Assume DST starting in 1920, as per Scott
Keltie & Epstein 1920.
* asia (Asia/Riyadh): Change standard-time transition from 1950
to 1947-03-14.  Add commentary citing Hunt 1961 and CAB 1946.
* australasia (Pacific/Chatham): Assume NZST - 45 min. before 1946.
Add commentary about this.
(Pacific/Pago_Pago): UT-11 from 1911 to 1950.
(WS, Pacific/Apia): Use NZ-style abbreviations.
Switch to "WSST" for Western Samoa standard time before 1950.
Add commentary about Samoa before 1950.
* NEWS: Document the above.

(cherry picked from commit f1ddf32f059c17fa5a1ec24f549d70db36dc5fa9)
---
 NEWS        |   16 ++++++++++++++++
 africa      |   10 +++++++---
 asia        |   23 ++++++++++++++++++++++-
 australasia |   40 ++++++++++++++++++++++++++++++++--------
 4 files changed, 77 insertions(+), 12 deletions(-)

diff --git a/NEWS b/NEWS
index ce2e33a..e87c519 100644
--- a/NEWS
+++ b/NEWS
@@ -40,6 +40,11 @@ Unreleased, experimental changes
     Prefer MSK/MSD for Moscow time in Russia, even in other cities.
     Similarly, prefer EET/EEST for eastern European time in Russia.
 
+    Change time zone abbreviations in (western) Samoa to use "ST" and
+    "DT" suffixes, as this is more likely to match common practice.
+    Prefix "W" to (western) Samoa time when its standard-time offset
+    disagrees with that of American Samoa.
+
     Time zone abbreviations have been updated for Japan's two time
     zones used 1896-1937.  JWST now stands for Western Standard
     Time, and JCST for Central Standard Time (formerly this was CJT).
@@ -67,9 +72,20 @@ Unreleased, experimental changes
     from 04-15 through 10-31; and in 1979 from 07-01 through 09-30.
     (Thanks to Yu-Cheng Chuang.)
 
+    Asia/Riyadh's transition to standard time is now 1947-03-14, not 1950.
+
     Europe/Helsinki's 1942 fall-back transition was October 4 at 01:00, not
     October 3 at 00:00.  (Thanks to Konstantin Hyppönen.)
 
+    Pacific/Pago_Pago has been changed from UTC-11:30 to UTC-11 for the period
+    from 1911 to 1950.
+
+    Pacific/Chatham has been changed to New Zealand standard time plus
+    45 minutes for the period before 1957, reflecting a 1956 remark in
+    the New Zealand parliament.
+
+    Africa/Accra is now assumed to have observed DST from 1920 through 1935.
+
     Time in Russia before 1927 or so has been corrected by a few seconds in
     the following zones: Europe/Moscow, Asia/Irkutsk, Asia/Tbilisi,
     Asia/Tashkent, Asia/Vladivostok, Asia/Yekaterinburg, Europe/Helsinki, and
diff --git a/africa b/africa
index 3d84d9b..e4ba52b 100644
--- a/africa
+++ b/africa
@@ -437,9 +437,13 @@ Zone	Africa/Banjul	-1:06:36 -	LMT	1912
 # Ghana
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 # Whitman says DST was observed from 1931 to "the present";
-# go with Shanks & Pottenger.
-Rule	Ghana	1936	1942	-	Sep	 1	0:00	0:20	GHST
-Rule	Ghana	1936	1942	-	Dec	31	0:00	0	GMT
+# Shanks & Pottenger say 1936 to 1942;
+# and September 1 to January 1 is given by:
+# Scott Keltie J, Epstein M (eds), The Statesman's Year-Book,
+# 57th ed. Macmillan, London (1920), OCLC 609408015, pp xxviii.
+# For lack of better info, assume DST was observed from 1920 to 1942.
+Rule	Ghana	1920	1942	-	Sep	 1	0:00	0:20	GHST
+Rule	Ghana	1920	1942	-	Dec	31	0:00	0	GMT
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone	Africa/Accra	-0:00:52 -	LMT	1918
 			 0:00	Ghana	%s
diff --git a/asia b/asia
index 4d9faeb..148671c 100644
--- a/asia
+++ b/asia
@@ -2439,8 +2439,29 @@ Zone	Asia/Qatar	3:26:08 -	LMT	1920	# Al Dawhah / Doha
 			3:00	-	AST
 
 # Saudi Arabia
+#
+# From Paul Eggert (2014-07-15):
+# Time in Saudi Arabia and other countries in the Arabian peninsula was not
+# standardized until relatively recently; we don't know when, and possibly it
+# has never been made official.  Richard P Hunt, in "Islam city yielding to
+# modern times", New York Times (1961-04-09), p 20, wrote that only airlines
+# observed standard time, and that people in Jidda mostly observed quasi-solar
+# time, doing so by setting their watches at sunrise to 6 o'clock (or to 12
+# o'clock for "Arab" time).
+#
+# The TZ database cannot represent quasi-solar time; airline time is the best
+# we can do.  The 1946 foreign air news digest of the U.S. Civil Aeronautics
+# Board (OCLC 42299995) reported that the "... Arabian Government, inaugurated
+# a weekly Dhahran-Cairo service, via the Saudi Arabian cities of Riyadh and
+# Jidda, on March 14, 1947".  Shanks & Pottenger guessed 1950; go with the
+# earlier date.
+#
+# Shanks & Pottenger also state that until 1968-05-01 Saudi Arabia had two
+# time zones; the other zone, at UTC+4, was in the far eastern part of
+# the country.  Ignore this, as it's before our 1970 cutoff.
+#
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
-Zone	Asia/Riyadh	3:06:52 -	LMT	1950
+Zone	Asia/Riyadh	3:06:52 -	LMT	1947 Mar 14
 			3:00	-	AST
 
 # Singapore
diff --git a/australasia b/australasia
index 605d8dd..4911e8d 100644
--- a/australasia
+++ b/australasia
@@ -466,7 +466,8 @@ Rule	Chatham	2008	max	-	Apr	Sun>=1	2:45s	0	S
 Zone Pacific/Auckland	11:39:04 -	LMT	1868 Nov  2
 			11:30	NZ	NZ%sT	1946 Jan  1
 			12:00	NZ	NZ%sT
-Zone Pacific/Chatham	12:13:48 -	LMT	1957 Jan  1
+Zone Pacific/Chatham	12:13:48 -	LMT	1868 Nov  2
+			12:15	-	CHAST	1946 Jan  1
 			12:45	Chatham	CHA%sT
 
 Link Pacific/Auckland Antarctica/McMurdo
@@ -528,7 +529,6 @@ Zone Pacific/Pitcairn	-8:40:20 -	LMT	1901		# Adamstown
 # American Samoa
 Zone Pacific/Pago_Pago	 12:37:12 -	LMT	1879 Jul  5
 			-11:22:48 -	LMT	1911
-			-11:30	-	SAMT	1950		# Samoa Time
 			-11:00	-	NST	1967 Apr	# N=Nome
 			-11:00	-	BST	1983 Nov 30	# B=Bering
 			-11:00	-	SST			# S=Samoa
@@ -603,15 +603,15 @@ Zone Pacific/Pago_Pago	 12:37:12 -	LMT	1879 Jul  5
 
 # Rule	NAME	FROM	TO	TYPE	IN	ON	AT	SAVE	LETTER/S
 Rule	WS	2010	only	-	Sep	lastSun	0:00	1	D
-Rule	WS	2011	only	-	Apr	Sat>=1	4:00	0	-
+Rule	WS	2011	only	-	Apr	Sat>=1	4:00	0	S
 Rule	WS	2011	only	-	Sep	lastSat	3:00	1	D
-Rule	WS	2012	max	-	Apr	Sun>=1	4:00	0	-
+Rule	WS	2012	max	-	Apr	Sun>=1	4:00	0	S
 Rule	WS	2012	max	-	Sep	lastSun	3:00	1	D
 # Zone	NAME		GMTOFF	RULES	FORMAT	[UNTIL]
 Zone Pacific/Apia	 12:33:04 -	LMT	1879 Jul  5
 			-11:26:56 -	LMT	1911
-			-11:30	-	SAMT	1950		# Samoa Time
-			-11:00	WS	WS%sT	2011 Dec 29 24:00
+			-11:30	-	WSST	1950
+			-11:00	WS	S%sT	2011 Dec 29 24:00 # S=Samoa
 			 13:00	WS	WS%sT
 
 # Solomon Is
@@ -804,7 +804,10 @@ Zone	Pacific/Wallis	12:15:20 -	LMT	1901
 #	 10:30	LHST	LHDT	Lord Howe*
 #	 11:30	NZMT	NZST	New Zealand through 1945
 #	 12:00	NZST	NZDT	New Zealand 1946-present
-#	 12:45	CHAST	CHADT	Chatham*
+#	 12:15	CHAST		Chatham through 1945*
+#	 12:45	CHAST	CHADT	Chatham 1946-present*
+#	 13:00	WSST	WSDT	(western) Samoa 2011-present*
+#	-11:30	WSST		Western Samoa through 1950*
 #	-11:00	SST		Samoa
 #	-10:00	HST		Hawaii
 #	- 8:00	PST		Pitcairn*
@@ -1429,6 +1432,19 @@ Zone	Pacific/Wallis	12:15:20 -	LMT	1901
 # that DST will begin on 2007-09-30 2008-04-06.
 # http://www.dia.govt.nz/diawebsite.nsf/wpg_URL/Services-Daylight-Saving-Daylight-saving-to-be-extended
 
+# From Paul Eggert (2014-07-14):
+# Chatham Island time was formally standardized on 1957-01-01 by
+# New Zealand's Standard Time Amendment Act 1956 (1956-10-26)
+# <http://www.austlii.edu.au/nz/legis/hist_act/staa19561956n100244.pdf>.
+# According to Google Books snippet view, a speaker in the New Zealand
+# parliamentary debates in 1956 said "Clause 78 makes provision for standard
+# time in the Chatham Islands.  The time there is 45 minutes in advance of New
+# Zealand time.  I understand that is the time they keep locally, anyhow."
+# For now, assume this practice goes back to the introduction of standard time
+# in New Zealand, as this would make Chatham Islands time almost exactly match
+# LMT back when New Zealand was at UTC+11:30; also, assume Chatham Islands did
+# not observe New Zealand's prewar DST.
+
 ###############################################################################
 
 
@@ -1546,7 +1562,7 @@ Zone	Pacific/Wallis	12:15:20 -	LMT	1901
 # Sacramento but it was changed a couple of years ago.
 
 
-# Samoa
+# (Western) Samoa and American Samoa
 
 # Howse writes (p 153, citing p 10 of the 1883-11-18 New York Herald)
 # that in 1879 the King of Samoa decided to change
@@ -1554,6 +1570,14 @@ Zone	Pacific/Wallis	12:15:20 -	LMT	1901
 # ordaining - by a masterpiece of diplomatic flattery - that
 # the Fourth of July should be celebrated twice in that year."
 
+# Although Shanks & Pottenger says they both switched to UTC-11:30
+# in 1911, and to UTC-11 in 1950. many earlier sources give UTC-11
+# for American Samoa, e.g., the US National Bureau of Standards
+# circular "Standard Time Throughout the World", 1932.
+# Assume American Samoa switched to UTC-11 in 1911, not 1950,
+# and that after 1950 they agreed until (western) Samoa skipped a
+# day in 2011.  Assume also that the Samoas follow the US and New
+# Zealand's "ST"/"DT" style of daylight-saving abbreviations.
 
 # Tonga
 
-- 
1.7.9

