Cada vez que se actualiza, se debe modificar un archivo maestro que sincroniza los relojes de casi todos los equipos del planeta. Esto permite que los horarios de aviones calcen, y las transacciones bancarias salgan en la hora correcta, sobre todo las compras y ventas de acciones que pueden cambiar de valor en segundos.
Este es el capitulo extraído directamente del código fuente de «tzdata2016d.tar.gz», la cuarta versión del 2016 de tzdata.
Contiene la historia completa de la razón de los cambios, la fuente que lo confirma, quien lo informa y luego el set de reglas que rige nuestro horario desde 1927 hasta hoy.
Vean el tamaño.
# ChileAhora, comparemos con un país que también tiene cambio de hora, como Finlandia
# From Paul Eggert (2015-04-03):
# Shanks & Pottenger says America/Santiago introduced standard time in
# 1890 and rounds its UTC offset to 70W40; guess that in practice this
# was the same offset as in 1916-1919. It also says Pacific/Easter
# standardized on 109W22 in 1890; assume this didn't change the clocks.
#
# Dates for America/Santiago from 1910 to 2004 are primarily from
# the following source, cited by Oscar van Vlijmen (2006-10-08):
# [1] Chile Law
# http://www.webexhibits.org/daylightsaving/chile.html
# This contains a copy of a this official table:
# Cambios en la hora oficial de Chile desde 1900 (retrieved 2008-03-30)
# http://web.archive.org/web/20080330200901/http://www.horaoficial.cl/cambio.htm
# [1] needs several corrections, though.
#
# The first set of corrections is from:
# [2] History of the Official Time of Chile
# http://www.horaoficial.cl/ing/horaof_ing.html (retrieved 2012-03-06). See:
# http://web.archive.org/web/20120306042032/http://www.horaoficial.cl/ing/horaof_ing.html
# This is an English translation of:
# Historia de la hora oficial de Chile (retrieved 2012-10-24). See:
# http://web.archive.org/web/20121024234627/http://www.horaoficial.cl/horaof.htm
# A fancier Spanish version (requiring mouse-clicking) is at:
# http://www.horaoficial.cl/historia_hora.html
# Conflicts between [1] and [2] were resolved as follows:
#
# - [1] says the 1910 transition was Jan 1, [2] says Jan 10 and cites
# Boletín No. 1, Aviso No. 1 (1910). Go with [2].
#
# - [1] says SMT was -4:42:45, [2] says Chile's official time from
# 1916 to 1919 was -4:42:46.3, the meridian of Chile's National
# Astronomical Observatory (OAN), then located in what is now
# Quinta Normal in Santiago. Go with [2], rounding it to -4:42:46.
#
# - [1] says the 1918 transition was Sep 1, [2] says Sep 10 and cites
# Boletín No. 22, Aviso No. 129/1918 (1918-08-23). Go with [2].
#
# - [1] does not give times for transitions; assume they occur
# at midnight mainland time, the current common practice. However,
# go with [2]'s specification of 23:00 for the 1947-05-21 transition.
#
# Another correction to [1] is from Jesper Nørgaard Welen, who
# wrote (2006-10-08), "I think that there are some obvious mistakes in
# the suggested link from Oscar van Vlijmen,... for instance entry 66
# says that GMT-4 ended 1990-09-12 while entry 67 only begins GMT-3 at
# 1990-09-15 (they should have been 1990-09-15 and 1990-09-16
# respectively), but anyhow it clears up some doubts too."
#
# Data for Pacific/Easter from 1910 through 1967 come from Shanks &
# Pottenger. After that, for lack of better info assume
# Pacific/Easter is always two hours behind America/Santiago;
# this is known to work for DST transitions starting in 2008 and
# may well be true for earlier transitions.
# From Eduardo Krell (1995-10-19):
# The law says to switch to DST at midnight [24:00] on the second SATURDAY
# of October.... The law is the same for March and October.
# (1998-09-29):
# Because of the drought this year, the government decided to go into
# DST earlier (saturday 9/26 at 24:00). This is a one-time change only ...
# (unless there's another dry season next year, I guess).
# From Julio I. Pacheco Troncoso (1999-03-18):
# Because of the same drought, the government decided to end DST later,
# on April 3, (one-time change).
# From Germán Poo-Caamaño (2008-03-03):
# Due to drought, Chile extends Daylight Time in three weeks. This
# is one-time change (Saturday 3/29 at 24:00 for America/Santiago
# and Saturday 3/29 at 22:00 for Pacific/Easter)
# The Supreme Decree is located at
# http://www.shoa.cl/servicios/supremo316.pdf
#
# From José Miguel Garrido (2008-03-05):
# http://www.shoa.cl/noticias/2008/04hora/hora.htm
# From Angel Chiang (2010-03-04):
# Subject: DST in Chile exceptionally extended to 3 April due to earthquake
# http://www.gobiernodechile.cl/viewNoticia.aspx?idArticulo=30098
#
# From Arthur David Olson (2010-03-06):
# Angel Chiang's message confirmed by Julio Pacheco; Julio provided a patch.
# From Glenn Eychaner (2011-03-28):
# http://diario.elmercurio.com/2011/03/28/_portada/_portada/noticias/7565897A-CA86-49E6-9E03-660B21A4883E.htm?id=3D{7565897A-CA86-49E6-9E03-660B21A4883E}
# In English:
# Chile's clocks will go back an hour this year on the 7th of May instead
# of this Saturday. They will go forward again the 3rd Saturday in
# August, not in October as they have since 1968.
# From Mauricio Parada (2012-02-22), translated by Glenn Eychaner (2012-02-23):
# As stated in the website of the Chilean Energy Ministry
# http://www.minenergia.cl/ministerio/noticias/generales/gobierno-anuncia-fechas-de-cambio-de.html
# The Chilean Government has decided to postpone the entrance into winter time
# (to leave DST) from March 11 2012 to April 28th 2012....
# Quote from the website communication:
#
# 6. For the year 2012, the dates of entry into winter time will be as follows:
# a. Saturday April 28, 2012, clocks should go back 60 minutes; that is, at
# 23:59:59, instead of passing to 0:00, the time should be adjusted to be 23:00
# of the same day.
# b. Saturday, September 1, 2012, clocks should go forward 60 minutes; that is,
# at 23:59:59, instead of passing to 0:00, the time should be adjusted to be
# 01:00 on September 2.
# From Steffen Thorsen (2013-02-15):
# According to several news sources, Chile has extended DST this year,
# they will end DST later and start DST earlier than planned. They
# hope to save energy. The new end date is 2013-04-28 00:00 and new
# start date is 2013-09-08 00:00....
# http://www.gob.cl/informa/2013/02/15/gobierno-anuncia-fechas-de-cambio-de-hora-para-el-ano-2013.htm
# From José Miguel Garrido (2014-02-19):
# Today appeared in the Diario Oficial a decree amending the time change
# dates to 2014.
# DST End: last Saturday of April 2014 (Sun 27 Apr 2014 03:00 UTC)
# DST Start: first Saturday of September 2014 (Sun 07 Sep 2014 04:00 UTC)
# http://www.diariooficial.interior.gob.cl//media/2014/02/19/do-20140219.pdf
# From Eduardo Romero Urra (2015-03-03):
# Today has been published officially that Chile will use the DST time
# permanently until March 25 of 2017
# http://www.diariooficial.interior.gob.cl/media/2015/03/03/1-large.jpg
#
# From Paul Eggert (2015-03-03):
# For now, assume that the extension will persist indefinitely.
# From Juan Correa (2016-03-18):
# The decree regarding DST has been published in today's Official Gazette:
# http://www.diariooficial.interior.gob.cl/versiones-anteriores/do/20160318/
# http://www.leychile.cl/Navegar?idNorma=1088502
# It does consider the second Saturday of May and August as the dates
# for the transition; and it lists DST dates until 2019, but I think
# this scheme will stick.
#
# From Paul Eggert (2016-03-18):
# For now, assume the pattern holds for the indefinite future.
# The decree says transitions occur at 24:00; in practice this appears
# to mean 24:00 mainland time, not 24:00 local time, so that Easter
# Island is always two hours behind the mainland.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Chile 1927 1931 - Sep 1 0:00 1:00 S
Rule Chile 1928 1932 - Apr 1 0:00 0 -
Rule Chile 1968 only - Nov 3 4:00u 1:00 S
Rule Chile 1969 only - Mar 30 3:00u 0 -
Rule Chile 1969 only - Nov 23 4:00u 1:00 S
Rule Chile 1970 only - Mar 29 3:00u 0 -
Rule Chile 1971 only - Mar 14 3:00u 0 -
Rule Chile 1970 1972 - Oct Sun>=9 4:00u 1:00 S
Rule Chile 1972 1986 - Mar Sun>=9 3:00u 0 -
Rule Chile 1973 only - Sep 30 4:00u 1:00 S
Rule Chile 1974 1987 - Oct Sun>=9 4:00u 1:00 S
Rule Chile 1987 only - Apr 12 3:00u 0 -
Rule Chile 1988 1990 - Mar Sun>=9 3:00u 0 -
Rule Chile 1988 1989 - Oct Sun>=9 4:00u 1:00 S
Rule Chile 1990 only - Sep 16 4:00u 1:00 S
Rule Chile 1991 1996 - Mar Sun>=9 3:00u 0 -
Rule Chile 1991 1997 - Oct Sun>=9 4:00u 1:00 S
Rule Chile 1997 only - Mar 30 3:00u 0 -
Rule Chile 1998 only - Mar Sun>=9 3:00u 0 -
Rule Chile 1998 only - Sep 27 4:00u 1:00 S
Rule Chile 1999 only - Apr 4 3:00u 0 -
Rule Chile 1999 2010 - Oct Sun>=9 4:00u 1:00 S
Rule Chile 2000 2007 - Mar Sun>=9 3:00u 0 -
# N.B.: the end of March 29 in Chile is March 30 in Universal time,
# which is used below in specifying the transition.
Rule Chile 2008 only - Mar 30 3:00u 0 -
Rule Chile 2009 only - Mar Sun>=9 3:00u 0 -
Rule Chile 2010 only - Apr Sun>=1 3:00u 0 -
Rule Chile 2011 only - May Sun>=2 3:00u 0 -
Rule Chile 2011 only - Aug Sun>=16 4:00u 1:00 S
Rule Chile 2012 2014 - Apr Sun>=23 3:00u 0 -
Rule Chile 2012 2014 - Sep Sun>=2 4:00u 1:00 S
Rule Chile 2016 max - May Sun>=9 3:00u 0 -
Rule Chile 2016 max - Aug Sun>=9 4:00u 1:00 S
# IATA SSIM anomalies: (1992-02) says 1992-03-14;
# (1996-09) says 1998-03-08. Ignore these.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone America/Santiago -4:42:46 - LMT 1890
-4:42:46 - SMT 1910 Jan 10 # Santiago Mean Time
-5:00 - CLT 1916 Jul 1 # Chile Time
-4:42:46 - SMT 1918 Sep 10
-4:00 - CLT 1919 Jul 1
-4:42:46 - SMT 1927 Sep 1
-5:00 Chile CL%sT 1932 Sep 1
-4:00 - CLT 1942 Jun 1
-5:00 - CLT 1942 Aug 1
-4:00 - CLT 1946 Jul 15
-4:00 1:00 CLST 1946 Sep 1 # central Chile
-4:00 - CLT 1947 Apr 1
-5:00 - CLT 1947 May 21 23:00
-4:00 Chile CL%sT
Zone Pacific/Easter -7:17:28 - LMT 1890
-7:17:28 - EMT 1932 Sep # Easter Mean Time
-7:00 Chile EAS%sT 1982 Mar 14 3:00u # Easter Time
-6:00 Chile EAS%sT
#
# Salas y Gómez Island is uninhabited.
# Other Chilean locations, including Juan Fernández Is, Desventuradas Is,
# and Antarctic bases, are like America/Santiago.
# Antarctic base using South American rules
# (See the file 'antarctica' for more.)
#
# Palmer, Anvers Island, since 1965 (moved 2 miles in 1968)
#
# From Ethan Dicks (1996-10-06):
# It keeps the same time as Punta Arenas, Chile, because, just like us
# and the South Pole, that's the other end of their supply line....
# I verified with someone who was there that since 1980,
# Palmer has followed Chile. Prior to that, before the Falklands War,
# Palmer used to be supplied from Argentina.
#
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone Antarctica/Palmer 0 - zzz 1965
-4:00 Arg AR%sT 1969 Oct 5
-3:00 Arg AR%sT 1982 May
-4:00 Chile CL%sT
# FinlandConsiderando que Finlandia pasa de 16 horas de Sol en verano, a poco más de 5 horas en invierno, los cambios de hora deberían ser más violentos en Finlandia, sin embargo es evidente que Chile lleva años asumiendo que los cambios de hora sirven de algo, cuando en la práctica el seguir cambiándolo muestra que no.
# From Hannu Strang (1994-09-25 06:03:37 UTC):
# Well, here in Helsinki we're just changing from summer time to regular one,
# and it's supposed to change at 4am...
# From Janne Snabb (2010-07-15):
#
# I noticed that the Finland data is not accurate for years 1981 and 1982.
# During these two first trial years the DST adjustment was made one hour
# earlier than in forthcoming years. Starting 1983 the adjustment was made
# according to the central European standards.
#
# This is documented in Heikki Oja: Aikakirja 2007, published by The Almanac
# Office of University of Helsinki, ISBN 952-10-3221-9, available online (in
# Finnish) at
# http://almanakka.helsinki.fi/aikakirja/Aikakirja2007kokonaan.pdf
#
# Page 105 (56 in PDF version) has a handy table of all past daylight savings
# transitions. It is easy enough to interpret without Finnish skills.
#
# This is also confirmed by Finnish Broadcasting Company's archive at:
# http://www.yle.fi/elavaarkisto/?s=s&g=1&ag=5&t=&a=3401
#
# The news clip from 1981 says that "the time between 2 and 3 o'clock does not
# exist tonight."
# From Konstantin Hyppönen (2014-06-13):
# [Heikki Oja's book Aikakirja 2013]
# http://almanakka.helsinki.fi/images/aikakirja/Aikakirja2013kokonaan.pdf
# pages 104-105, including a scan from a newspaper published on Apr 2 1942
# say that ... [o]n Apr 2 1942, 24 o'clock (which means Apr 3 1942,
# 00:00), clocks were moved one hour forward. The newspaper
# mentions "on the night from Thursday to Friday"....
# On Oct 4 1942, clocks were moved at 1:00 one hour backwards.
#
# From Paul Eggert (2014-06-14):
# Go with Oja over Shanks.
# Rule NAME FROM TO TYPE IN ON AT SAVE LETTER/S
Rule Finland 1942 only - Apr 2 24:00 1:00 S
Rule Finland 1942 only - Oct 4 1:00 0 -
Rule Finland 1981 1982 - Mar lastSun 2:00 1:00 S
Rule Finland 1981 1982 - Sep lastSun 3:00 0 -
# Milne says Helsinki (Helsingfors) time was 1:39:49.2 (official document);
# round to nearest.
# Zone NAME GMTOFF RULES FORMAT [UNTIL]
Zone Europe/Helsinki 1:39:49 - LMT 1878 May 31
1:39:49 - HMT 1921 May # Helsinki Mean Time
2:00 Finland EE%sT 1983
2:00 EU EE%sT
Chile debería quedar en UTC-5, como su geografía lo estipula. Eso da una buena hora de salida del Sol, para que la gente pueda salir de sus casas con luz solar. Ahora el que a su regreso ya esté oscuro, es un problema de la jornada laboral.
