proposed tz patches for Mexico, Nunavut, Vostok, etc.

Jesper Nørgaard jnorgard at
Sun Apr 1 17:23:40 UTC 2001

* For what it's worth, I think that the AEST/AEDT suggestion for Australia is the
  most logical one to adopt. At present EST might mean Eastern Standard Time
  (in the US or Mexico), and Eastern Standard Time in Australia, and Eastern
  Summer Time in Australia, which makes it convenient to try to adopt a different
  and less redundant naming. Although as Paul Eggert points out there is not
  a consistent use of AEST/AEDT (e.g. by mail servers etc.) this seems to be
  the most used alternative acronym to EST/EST. I use AEST/AEDT already
  in my program World Time Explorer (Time Zone Converter).

* A small spelling mistake: the reference to "Palabra" contains the date 2000-03-31,
  it should be 2001-03-31.


Jesper Nørgaard Welen
Email: jnorgard at	
CIMMYT  -  Centro Internacional de Mejoramiento de Maíz y Trigo
Dirección: CIMMYT Int. c/o Jesper Nørgaard
Km. 45, Carretera México-Veracruz
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Texcoco, Edo. de México
CP 56130   MEXICO
Tel.:	+52 (5) 58-04-20-04  ext. 1374
Fax:	+52 (5) 58-04-75-58
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Check out my free program World Time Explorer:

From: 	Paul Eggert[SMTP:eggert at]
Sent: 	Sábado 31 de Marzo de 2001 21:37
To: 	tz at
Subject: 	proposed tz patches for Mexico, Nunavut, Vostok, etc.

Jesper Norgaard's letter about what actually happened in Mexico this
morning prompted me to propose the tz patches enclosed below, which
accumulate most of the changes recently proposed.  The patches for
Mexico are the most important, though Nunavut and Vostok also need
fixes now so that current time stamps are reported correctly.

Sorry, I haven't had time to think through the issue of Australian
time zone abbreviations yet.  If I recall correctly, we have so far:

  * one well-researched proposal to change from EST/EST etc to AEST/AEDT etc; 
  * one second.
  * one dissenting vote to leave it at is.
  * my own brief research indicating that Australians themselves are
     not consistent

Right now we have to get the Mexican patches out, so I'll leave the
Australian abbreviations alone for now, but I'd like more votes and/or
research if possible.

Anyway, here is a summary of the patch proposed below:

* Despite earlier predictions, America/Monterrey and America/Chihuahua did
  _not_ change their clocks today.  They will change at the same time as
  the rest of Mexico.  (Thanks to Jesper Norgaard for this.)

* Nunavut went back to its pre-1999 ways, effective today.  (Thanks to
  Rives McDow for this.)

* Antarctica/Vostok is at UTC+6, not UTC+3.  The message I got from
  Vostok was a bit confusing; perhaps nobody in Antarctica observes
  DST, contrary to our tables?  We need more info about this.  (Thanks
  to Lee Hotz for this.)

* Correct several errors for Dutch daylight saving time before World
  War II.  (Thanks to Robert H. van Gent for this.)

* Alaska switched from Asian to American dates on 1867-10-18.  We can't
  capture the Julian-to-Gregorian switch that occurred at the same time,
  but at least we can capture the 24-hour time zone change.
  (Thanks to Robert H. van Gent for this.)

* The Philippines switched from American to Asian dates on 1844-12-31.
  (Thanks to Robert H. van Gent for obtaining a copy of the
  proclamation.)  For now, guess the Ladrones switched at the same

The following changes affect commentary only:

* Add references to Vzic (a tz-to-VTIMEZONE compiler), and to
  possible XML schemata for tz data.

* Add references to a history of the International Date Line, and to
  Netherlands time zone history.  (Thanks to Robert H. van Gent for

* Update the status of various Antarctic stations, some of which have

* Update the instructions for running the XHTML validator.


 # James F. Smith writes in today's LA Times
 # </a>
 # * Sonora will continue to observe standard time.
-# * Border states including Baja California, Chihuahua, and Nuevo Leon
-#   will use US rules,
 # * Last week Mexico City's mayor Andres Manuel Lopez Obrador decreed that
 #   the Federal District will not adopt DST.
 # * 4 of 16 district leaders announced they'll ignore the decree.
 # * The decree does not affect federal-controlled facilities including
 #   the airport, banks, hospitals, and schools.
-# For now we'll assume that the Federal District will bow to federal rules
-# and that border states and Durango will stick with US rules.
+# For now we'll assume that the Federal District will bow to federal rules.
+# From Jesper Norgaard (2001-04-01):
+# I found some references to the Mexican application of daylight
+# saving, which modifies what I had already sent you, stating earlier
+# that a number of northern Mexican states would go on daylight
+# saving. The modification reverts this to only cover Baja California
+# (Norte), while all other states (except Sonora, who has no daylight
+# saving all year) will follow the original decree of president
+# Vicente Fox, starting daylight saving May 6, 2001 and ending
+# September 30, 2001.
+# References: "Diario de Monterrey" <>
+# Palabra <> (2000-03-31)
 Rule	Mexico	1939	only	-	Feb	5	0:00	1:00	D
@@ -1333,8 +1361,7 @@ Zone America/Merida	-5:58:28 -	LMT	1922 
 Zone America/Monterrey	-6:41:16 -	LMT	1921 Dec 31 23:18:44
 			-6:00	-	CST	1988
 			-6:00	US	C%sT	1989
-			-6:00	Mexico	C%sT	2001
-			-6:00	US	C%sT
+			-6:00	Mexico	C%sT
 # Central Mexico
 Zone America/Mexico_City -6:36:36 -	LMT	1922 Jan  1  0:23:24
 			-7:00	-	MST	1927 Jun 10 23:00
@@ -1353,8 +1380,7 @@ Zone America/Chihuahua	-7:04:20 -	LMT	19
 			-6:00	-	CST	1996
 			-6:00	Mexico	C%sT	1998
 			-6:00	-	CST	1998 Apr Sun>=1 3:00
-			-7:00	Mexico	M%sT	2001
-			-7:00	US	M%sT
+			-7:00	Mexico	M%sT
 # Sonora
 Zone America/Hermosillo	-7:23:52 -	LMT	1921 Dec 31 23:36:08
 			-7:00	-	MST	1927 Jun 10 23:00

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