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<?xml version="1.0" encoding="US-ASCII"?>
<!DOCTYPE html
PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<title>Sources for Time Zone and Daylight Saving Time Data</title>
<link rel="schema.DC" href="http://purl.org/DC/elements/1.1/" />
<meta http-equiv="Content-type" content='text/html; charset="US-ASCII"' />
<meta name="DC.Creator" content="Eggert, Paul" />
<meta name="DC.Contributor" content="Olson, Arthur David" />
<meta name="DC.Date" content="2004-09-22" />
<meta name="DC.Description"
content="Sources of information about time zones and daylight saving time" />
<meta name="DC.Identifier" content="http://www.twinsun.com/tz/tz-link.htm" />
<meta name="Keywords"
content="database,daylight saving,DST,time zone,timezone,tz,zoneinfo" />
</head>
<body>
<h1>Sources for Time Zone and Daylight Saving Time Data</h1>
<address>
@(#)tz-link.htm 7.44
</address>
<p>
Please send corrections to this web page to the
<a href="mailto:tz@elsie.nci.nih.gov">time zone mailing list</a>.</p>
<h2>The <code>tz</code> database</h2>
<p>
The public-domain time zone database contains code and data
that represent the history of local time
for many representative locations around the globe.
It is updated periodically to reflect changes made by political bodies
to <abbr title="Coordinated Universal Time">UTC</abbr>
offsets and daylight-saving rules.
This database (often called <code>tz</code> or <code>zoneinfo</code>)
is used by several implementations,
including
<a href="http://www.gnu.org/software/libc/">the
<acronym title="GNU's Not Unix">GNU</acronym>
C Library</a> used in
<a href="http://www.linux.org/"><acronym>GNU</acronym>/Linux</a>,
<a href="http://www.freebsd.org/">FreeBSD</a>,
<a href="http://www.netbsd.org/">NetBSD</a>,
<a href="http://www.openbsd.org/">OpenBSD</a>,
<a href="http://www.cygwin.com/">Cygwin</a>,
<a href="http://www.delorie.com/djgpp/"><abbr
title="DJ's GNU Programming Platform">DJGPP</abbr></a>,
<a href="http://www.hp.com/products1/unix/operating/">HP-UX</a>,
<a href="http://www.sgi.com/developers/technology/irix/">IRIX</a>,
<a href="http://www.apple.com/macosx/">Mac OS X</a>,
<a href="http://h71000.www7.hp.com/">OpenVMS</a>,
<a href="http://wwws.sun.com/software/solaris/">Solaris</a>,
<a href="http://h30097.www3.hp.com/">Tru64</a>, and
<a href="http://www.sco.com/products/unixware/">UnixWare</a>.</p>
<p>
Each location in the database represents a national region where all
clocks keeping local time have agreed since 1970.
Locations are identified by continent or ocean and then by the name of
the location, which is typically the largest city within the region.
For example, <code>America/New_York</code>
represents most of the <abbr title="United States">US</abbr> eastern time zone;
<code>America/Indianapolis</code> represents most of Indiana, which
uses eastern time without daylight saving time (<abbr
title="daylight saving time">DST</abbr>);
<code>America/Detroit</code> represents most of Michigan, which uses
eastern time but with different <abbr>DST</abbr> rules in 1975;
and other entries represent smaller regions like Starke County,
Kentucky, which switched from central to eastern time in 1991.
To use the database on an extended <a
href="http://www.pasc.org/#POSIX"><abbr
title="Portable Operating System Interface">POSIX</abbr></a>
implementation set the <code>TZ</code> environment variable to
the location's full name, e.g., <code>TZ="America/New_York"</code>.</p>
<p>
In the <code>tz</code> database's
<a href="ftp://elsie.nci.nih.gov/pub/"><abbr
title="File Transfer Protocol">FTP</abbr> distribution</a>
the code is in the file <code>tzcode<var>C</var>.tar.gz</code>,
where <code><var>C</var></code> is the code's version;
similarly, the data are in <code>tzdata<var>D</var>.tar.gz</code>,
where <code><var>D</var></code> is the data's version.
The following shell commands download
these files to a <acronym>GNU</acronym>/Linux or similar host;
see the downloaded
<code>README</code> file for what to do next.</p>
<pre style="margin-left: 2em"><code><a href="http://www.gnu.org/software/wget/">wget</a> 'ftp://elsie.nci.nih.gov/pub/tz*.tar.gz'
<a href="http://www.gnu.org/software/gzip/">gzip</a> -dc tzcode*.tar.gz | <a href="http://www.gnu.org/software/tar/">tar</a> -xf -
gzip -dc tzdata*.tar.gz | tar -xf -
</code></pre>
<p>
The code lets you compile the <code>tz</code> source files into
machine-readable binary files, one for each location. It also lets
you read a <code>tz</code> binary file and interpret time stamps for that
location.</p>
<p>
The data are by no means authoritative. If you find errors, please
send changes to the <a href="mailto:tz@elsie.nci.nih.gov">time zone
mailing list</a>. You can also <a
href="mailto:tz-request@elsie.nci.nih.gov">subscribe</a> to the
mailing list, retrieve the <a
href="ftp://elsie.nci.nih.gov/pub/tzarchive.gz">archive of old
messages</a> (in gzip compressed format), or retrieve <a
href="ftp://munnari.oz.au/pub/oldtz/">archived older versions of code
and data</a>; there is also a smaller <a
href="http://public.planetmirror.com/pub/timezone/"><abbr
title="Hypertext Transfer Protocol">HTTP</abbr>
mirror</a>.</p>
<p>
The Web has several other sources for time zone and daylight saving time data.
Here are some recent links that may be of interest.
</p>
<h2>Web pages using recent versions of the <code>tz</code> database</h2>
<ul>
<li><a href="http://twiki.org/cgi-bin/xtra/tzdate">Date and Time Gateway</a>
is a text-based point-and-click interface to tables of current time
throughout the world.</li>
<li>Fancier web interfaces, roughly in ascending order of complexity, include:
<ul>
<li><a
href="http://www.convertit.com/Go/ConvertIt/World_Time/Current_Time.ASP">Current
Time in 1000 Places</a></li>
<li><a href="http://timezoneconverter.com/">Time Zone Converter</a></li>
</ul></li>
<li><a href="http://www.timeanddate.com/worldclock/">The World Clock -
Time Zones</a>
is a web interface to a time zone database derived from
<code>tz</code>'s.</li>
</ul>
<h2>Other time zone database formats</h2>
<ul>
<li>The <a href="ftp://ftp.rfc-editor.org/in-notes/rfc2445.txt">
Internet Calendaring and Scheduling Core Object Specification
(iCalendar)</a> specification published by the (now-concluded) <a
href="http://www.ietf.org/html.charters/OLD/calsch-charter.html"><abbr
title="Internet Engineering Task Force">IETF</abbr>
Calendaring and Scheduling Working Group (<abbr
title="Calendaring and Scheduling Working Group">calsch</abbr>)</a>
covers time zone
data; see its VTIMEZONE calendar component.</li>
<li>The <a
href="http://lists.w3.org/Archives/Public/www-rdf-calendar/">www-rdf-calendar</a>
list discusses <a
href="http://www.w3.org/RDF/"><abbr
title="Resource Description Framework">RDF</abbr></a>-based calendar
and group scheduling systems, and has a <a
href="http://www.w3.org/2002/12/cal/#tzd">workspace on time zone
data</a> converted from <code>tz</code>. An earlier <a
href="http://www.w3.org/2000/01/foo">schema</a> was sketched out by <a
href="http://www.w3.org/People/Berners-Lee/">Tim Berners-Lee</a>.</li>
<li><a
href="http://www.calsch.org/ietf/archives/draft-ietf-calsch-many-xcal-02.txt"><abbr
title="XML DTD for iCalendar">XCal</abbr></a>
was a draft <a
href="http://www.w3.org/XML/"><abbr
title="Extensible Markup Language">XML</abbr></a> document type
definition that corresponded to iCalendar.</li>
</ul>
<h2>Other <code>tz</code> compilers</h2>
<ul>
<li><a href="http://www.dachaplin.dsl.pipex.com/vzic">Vzic iCalendar
Timezone Converter</a> describes a program Vzic that compiles
<code>tz</code> source into iCalendar-compatible VTIMEZONE files.
Vzic is freely
available under the <a
href="http://www.gnu.org/copyleft/gpl.html"><acronym>GNU</acronym>
General Public License (<abbr
title="General Public License">GPL</abbr>)</a>.</li>
<li><a
href="http://search.cpan.org/dist/DateTime-TimeZone/">DateTime::TimeZone</a>
contains a script <code>parse_olson</code> that compiles
<code>tz</code> source into <a href="http://www.perl.org/">Perl</a>
modules. It is part of the Perl <a
href="http://datetime.perl.org/">DateTime Project</a>, which is freely
available under both the <abbr>GPL</abbr> and the Perl Artistic
License. DateTime::TimeZone also contains a script
<code>tests_from_zdump</code> that generates test cases for each clock
transition in the <code>tz</code> database.</li>
<li><a href="http://oss.software.ibm.com/icu/"><abbr
title="International Components for Unicode">ICU</abbr></a>
contains a C/C++ library for internationalization that
has a compiler from <samp>tz</samp> source
into an <abbr>ICU</abbr>-specific format.
<abbr>ICU</abbr> is freely available under a
<abbr title="Berkeley Software Distribution">BSD</abbr>-style license.</li>
<li><a href="http://joda-time.sourceforge.net/">Joda Time - Java date
and time <abbr title="Application Program Interface">API</abbr></a>
contains a class
<code>org.joda.time.tz.ZoneInfoCompiler</code> that compiles
<code>tz</code> source into a Joda-specific binary format. Joda Time
is freely available under a <abbr>BSD</abbr>-style license.</li>
<li><a href="http://sourceforge.net/projects/pytz/">PyTZ - Python Time
Zone Library</a> compiles <code>tz</code> source into
<a href="http://www.python.org/">Python</a>.
It is freely available under a <abbr>BSD</abbr>-style license.</li>
</ul>
<h2>Other <code>tz</code> binary file readers</h2>
<ul>
<li>The <a
href="http://www.gnu.org/software/libc/"><acronym>GNU</acronym> C
Library</a>
has an independent, thread-safe implementation of
a <code>tz</code> binary file reader.
This library is freely available under the
<a href="http://www.gnu.org/copyleft/lesser.html">
<acronym>GNU</acronym> Lesser General Public License
(<abbr title="Lesser General Public License">LGPL</abbr>)</a>,
and is widely used in <acronym>GNU</acronym>/Linux systems.</li>
<li><a href="http://www.bmsi.com/java/#TZ">ZoneInfo.java</a>
is a <code>tz</code> binary file reader written in Java.
It is freely available under the <acronym>GNU</acronym>
<abbr>LGPL</abbr>.</li>
<li><a href="http://s.keim.free.fr/tz/doc.html">Python time zones</a>
is a <code>tz</code> binary file reader written in Python.
It is freely available under a <abbr>BSD</abbr>-style license.</li>
</ul>
<h2>Other <code>tz</code>-based time zone conversion software</h2>
<ul>
<li><a href="http://java.sun.com/">Sun Java</a> releases since 1.4
contain a copy of a subset of a recent <samp>tz</samp> database in a
Java-specific format.</li>
<li><a
href="http://www1.tip.nl/~t876506/AboutTimeZonesHC.html">HyperCard
time zones calculator</a> is a HyperCard stack.</li>
<li><a
href="http://www.cimmyt.org/timezone/">World Time Explorer</a> is a
Microsoft Windows program.</li>
</ul>
<h2>Other time zone databases</h2>
<ul>
<li><a href="http://www.astro.com/cgi/aq.cgi?lang=e">Atlas Query</a>
is Astrodienst's Web version of Shanks's
excellent time zone history atlases published in both <a
href="http://astrocom.com/products/software.php?software_id=ibmwboth">computer
and book form</a> by <a
href="http://astrocom.com/">Astro Communications Services</a>.</li>
<li><a href="http://worldtime.com/">WORLDTIME: interactive atlas,
time info, public holidays</a>
contains information on local time, sunrise and sunset,
and public holidays in several hundred cities around the world.</li>
<li><a href="http://www.worldtimeserver.com/">World Time Server</a>
is another time zone database.</li>
<li><a href="http://tycho.usno.navy.mil/tzones.html">World Time Zones</a>
contains data from the Time Service Department of the
<abbr>US</abbr> Naval Observatory, used as the source
for the <code>usno*</code> files in the <code>tz</code> distribution.</li>
<li><a href="http://www.airportcitycodes.com/aaa/">Airlines, Airplanes
and Airports</a> lists current standard times for thousands of
airports around the world. This seems to be derived from
the <a href="http://www.iata.org/ps/publications/9179.htm">Standard
Schedules Information Manual</a> of the
the <a href="http://www.iata.org/">International Air Transport
Association</a>,
which gives current time zone rules for
all the airports served by commercial aviation.</li>
</ul>
<h2>Maps</h2>
<ul>
<li>The <a href="http://www.odci.gov/">United States Central
Intelligence Agency (<abbr
title="Central Intelligence Agency">CIA</abbr>)</a> publishes a <a
href="http://www.odci.gov/cia/publications/factbook/reference_maps/pdf/time_zones.pdf">time
zone map</a>; the
<a
href="http://www.lib.utexas.edu/maps/world.html">Perry-Castañeda
Library Map Collection</a>
of the University of Texas at Austin has copies of
recent editions.
The pictorial quality is good,
but the maps do not indicate summer time,
and parts of the data are a few years out of date.</li>
<li><a href="http://worldtimezone.com/">Current time around the world
and standard time zones map of the world</a>
has several fancy time zone maps; it covers Russia particularly well.
The maps' pictorial quality is not quite as good as the
<abbr>CIA</abbr>'s
but the maps are more up to date.</li>
</ul>
<h2>Time zone boundaries</h2>
<ul>
<li><a href="http://www.statoids.com/statoids.html">Administrative Divisions
of Countries ("Statoids")</a> contains detailed lists of
<code>tz</code>-related zone subdivision data.</li>
<li><a href="http://home-4.tiscali.nl/~t876506/Multizones.html">Time
zone boundaries for multizone countries</a> summarizes legal
boundaries between time zones within countries.</li>
<li>Manifold.net's <a
href="http://www.manifold.net/download/freemaps.html">Free Maps and
<acronym title="Geographic Information Systems">GIS</acronym>
Data</a> includes a Manifold-format map of
world time zone boundaries distributed under the
<abbr>GPL</abbr>.</li>
<li>The <abbr>US</abbr> Geological Survey's National Atlas of
the United States
publishes the <a href="http://www.nationalatlas.gov/timeznm.html">Time
Zones of the United States</a> in the public domain.</li>
<li>The GeoCommunity lists several commercial sources for <a
href="http://spatialnews.geocomm.com/features/timezones/">International
Time Zones and Time Zone Data</a>.</li>
</ul>
<h2>Civil time concepts and history</h2>
<ul>
<li><a href="http://physics.nist.gov/time">A Walk through Time</a>
surveys the evolution of timekeeping.</li>
<li><a href="http://webexhibits.org/daylightsaving/">About Daylight
Saving Time - History, rationale, laws & dates</a>
is an overall history of <abbr>DST</abbr>.</li>
<li><a href="http://toi.iriti.cnr.it/">The
Time of Internet</a>
describes time zones and daylight saving time,
with diagrams.
The time zone map is out of date, however.</li>
<li><a href="http://www.phys.uu.nl/~vgent/idl/idl.htm">A History of
the International Date Line</a> tells the story of the most important
time zone boundary.</li>
<li><a href="http://www.statoids.com/tconcept.html">Basic Time
Zone Concepts</a> discusses terminological issues behind time zones.</li>
</ul>
<h2>National histories of legal time</h2>
<dl>
<dt>Australia</dt>
<dd>The Community Relations Division of the New South Wales
(<abbr title="New South Wales">NSW</abbr>)
Attorney General's Department maintains a <a
href="http://www.lawlink.nsw.gov.au/crd.nsf/pages/time2">history of
daylight saving in <abbr>NSW</abbr></a>.</dd>
<dt>Austria</dt>
<dd>The Federal Office of Metrology and Surveying publishes a
table of <a href="http://www.metrologie.at/pdf/sommerzeit.pdf"
hreflang="de">daylight saving time in Austria (in German)</a>.</dd>
<dt>Belgium</dt>
<dd>The Royal Observatory of Belgium maintains a table of <a
href="http://www.astro.oma.be/GENERAL/INFO/nli001a.html"
hreflang="nl">time in Belgium (in Dutch)</a>.</dd>
<dt>Brazil</dt>
<dd>The Time Service Department of the National Observatory
records <a href="http://pcdsh01.on.br/DecHV.html"
hreflang="pt-BR">Brazil's daylight saving time decrees (in
Portuguese)</a>.</dd>
<dt>Canada</dt>
<dd>The Institute for National Measurement Standards publishes current
and some older information about <a
href="http://inms-ienm.nrc-cnrc.gc.ca/time_services/daylight_savings_e.html">Time
Zones & Daylight Saving Time</a>.</dd>
<dt>Chile</dt>
<dd>WebExhibits publishes a <a
href="http://webexhibits.org/daylightsaving/chile.html"
hreflang="es">history of official time (in Spanish)</a> originally
written by the Chilean Hydrographic and Oceanographic Service.</dd>
<dt>Germany</dt>
<dd>The National Institute for Science and Technology maintains the <a
href="http://www.ptb.de/en/org/4/44/441/dars_e.htm">Realisation of
Legal Time in Germany</a>.</dd>
<dt>Israel</dt>
<dd>The Interior Ministry periodically issues <a
href="ftp://ftp.cs.huji.ac.il/pub/tz/announcements/"
hreflang="he">announcements (in Hebrew)</a>.</dd>
<dt>Mexico</dt>
<dd>The Investigation and Analysis Service of the Mexican Library of
Congress has published a <a
href="http://www.cddhcu.gob.mx/bibliot/publica/inveyana/polisoc/horver/"
hreflang="es">history of Mexican local time (in Spanish)</a>.</dd>
<dt>Malaysia</dt>
<dd>See Singapore below.</dd>
<dt>Netherlands</dt>
<dd><a href="http://www.phys.uu.nl/~vgent/wettijd/wettijd.htm"
hreflang="nl">Legal time in the Netherlands (in Dutch)</a>
covers the history of local time in the Netherlands from ancient times.</dd>
<dt>New Zealand</dt>
<dd>The Department of Internal Affairs maintains a brief history <a
href="http://www.dia.govt.nz/diawebsite.nsf/wpg_URL/Resource-material-Information-We-Provide-About-Daylight-Saving">about
daylight saving</a>. The privately-maintained <a
href="http://www.astrologyhouse.co.nz/timechanges.htm">Time Changes in
New Zealand</a> has more details.</dd>
<dt>Singapore</dt>
<dd><a
href="http://www.math.nus.edu.sg/aslaksen/teaching/timezone.html">Why
is Singapore in the "Wrong" Time Zone?</a> details the
history of legal time in Singapore and Malaysia.</dd>
<dt>United Kingdom</dt>
<dd><a
href="http://www.srcf.ucam.org/~jsm28/british-time/">History of
legal time in Britain</a> discusses in detail the country
with perhaps the best-documented history of clock adjustments.
The National Physical Laboratory also maintains an <a
href="http://www.npl.co.uk/time/summer_time_archive.html">archive
of summer time dates</a>.</dd>
</dl>
<h2>Precision timekeeping</h2>
<ul>
<li><a
href="http://literature.agilent.com/litwebbin/purl.cgi?org_id=tmo&pub_id=5965-7984E">The
Science of Timekeeping</a> is a thorough introduction
to the theory and practice of precision timekeeping.</li>
<li><a href="http://www.ntp.org/"><abbr
title="Network Time Protocol">NTP</abbr>: The Network
Time Protocol</a>
discusses how to synchronize clocks of
Internet hosts.</li>
<li><a href="http://gauss.gge.unb.ca/GMT.UT.and.the.RGO.html">A Few
Facts Concerning <abbr title="Greenwich Mean Time">GMT</abbr>, <abbr
title="Universal Time">UT</abbr>, and
the <abbr title="Royal Greenwich Observatory">RGO</abbr></a>
answers questions like "What is the
difference between <abbr>GMT</abbr> and <abbr>UTC</abbr>?"</li>
<li><a
href="http://www.gb.nrao.edu/~rfisher/Ephemerides/times.html">Astronomical
Times</a> explains more abstruse astronomical time scales like
<abbr title="Terrestrial Dynamic Time">TDT</abbr>,
<abbr title="Geocentric Coordinate Time">TCG</abbr>, and
<abbr title="Barycentric Dynamic Time">TDB</abbr>.</li>
<li>The <a href="http://www.iau.org/"><abbr
title="International Astronomical Union">IAU</abbr></a>'s <a
href="http://www.iau-sofa.rl.ac.uk/"><acronym
title="Standards Of Fundamental Astronomy">SOFA</acronym></a>
initiative publishes Fortran
code for converting among time scales like
<abbr title="International Atomic Time">TAI</abbr>,
<abbr>TDB</abbr>, <abbr>TDT</abbr> and
<abbr>UTC</abbr>.</li>
<li><a href="http://www.jpl.nasa.gov/basics/bsf2-3.htm">Basics of
Space Flight - Reference Systems - Time Conventions</a>
briefly explains interplanetary space flight timekeeping.</li>
<li><a
href="http://www.giss.nasa.gov/tools/mars24/help/notes.html">Technical
Notes on Mars Solar Time as Adopted by the Mars24 Sunclock</a> briefly
describes Mars Coordinated Time (<abbr
title="Mars Coordinated Time">MTC</abbr>) and the
diverse local time
scales used by each landed mission on Mars.</li>
<li><a
href="http://hpiers.obspm.fr/eop-pc/products/bulletins/bulletins.html">Bulletins
maintained by the
<abbr title="International Earth Rotation Service">IERS</abbr>
<abbr title="Earth Orientation Parameters">EOP</abbr>
(<abbr title="Product Center">PC</abbr>)</a> contains official publications of
the Earth Orientation Parameters Product Center of the
International Earth Rotation Service, the committee that decides
when leap seconds occur.</li>
<li>The <a
href="http://www.mail-archive.com/leapsecs@rom.usno.navy.mil/">Leap
Second Discussion List</a> covers <a
href="http://gauss.gge.unb.ca/papers.pdf/gpsworld.november99.pdf">McCarthy
and Klepczynski's proposal to discontinue leap seconds</a>, published in <a
href="http://www.gpsworld.com/"><abbr
title="Global Positioning System">GPS</abbr> World</a>
<strong>10</strong>, 11
(1999-11), 50–57 and discussed further in R. A. Nelson et al.,
<a href="http://www.cl.cam.ac.uk/~mgk25/time/metrologia-leapsecond.pdf">The
leap second: its history and possible future</a>,
<a href="http://www.bipm.fr/metrologia/metrologia.html">Metrologia</a>
<strong>38</strong> (2001), 509–529.
<a href="http://www.ucolick.org/~sla/leapsecs/onlinebib.html">The
Future of Leap Seconds</a> catalogs information about this
contentious issue.</li>
</ul>
<h2>Time notation</h2>
<ul>
<li>
<a href="http://www.cl.cam.ac.uk/~mgk25/iso-time.html">A Summary of
the International Standard Date and Time Notation</a> is a good
summary of
<abbr title="International Organization for Standardization">ISO</abbr>
8601:1988 - Data elements and interchange formats - Information interchange
- Representation of dates and times (which has been superseded by
<a
href="http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=26780"><abbr>ISO</abbr>
8601:2000</a>).</li>
<li>
Section 3.3 of <a
href="ftp://ftp.rfc-editor.org/in-notes/rfc2822.txt">Internet
<abbr title="Request For Comments">RFC</abbr> 2822</a>
specifies the time notation used in email and <a
href="ftp://ftp.rfc-editor.org/in-notes/rfc2616.txt"><abbr>HTTP</abbr></a>
headers.</li>
<li>
<a href="ftp://ftp.rfc-editor.org/in-notes/rfc3339.txt">Internet
<abbr>RFC</abbr> 3339</a> specifies an <abbr>ISO</abbr> 8601
profile for use in new Internet
protocols.</li>
<li>
<a href="http://www.exit109.com/~ghealton/y2k/yrexamples.html">The
Best of Dates, the Worst of Dates</a> covers many problems encountered
by software developers when handling dates and time stamps.</li>
<li><a
href="http://oss.software.ibm.com/cvs/icu/~checkout~/icuhtml/design/formatting/time_zone_localization.html">Time
Zone Localization</a> is a proposed mechanism for localizing time zone
labels and abbreviations; for example, one might use it to specify
Russian translations for "Eastern European Summer Time",
"<abbr title="Eastern European Summer Time">EEST</abbr>",
and <code>Europe/Bucharest</code>.</li>
<li> Alphabetic time zone abbreviations should not be used as unique
identifiers for <abbr>UTC</abbr> offsets as they are ambiguous in
practice. For example, "<abbr>EST</abbr>" denotes 5 hours behind
<abbr>UTC</abbr> in English-speaking North America, but it denotes 10
or 11 hours ahead of <abbr>UTC</abbr> in Australia; and
French-speaking North Americans prefer
"<abbr title="Heure Normale de l'Est">HNE</abbr>" to
"<abbr>EST</abbr>". For <abbr>POSIX</abbr> the <code>tz</code>
database contains English abbreviations for all time stamps but in
many cases these are merely inventions of the database
maintainers.</li>
</ul>
<h2>Related indexes</h2>
<ul>
<li><a href="tz-art.htm">Time and the Arts</a></li>
<li><a href="http://dmoz.org/Reference/Time/">Open Directory -
Reference: Time</a></li>
<li><a href="http://directory.google.com/Top/Reference/Time/">Google Directory
- Reference > Time</a></li>
<li><a href="http://dir.yahoo.com/Science/Measurements_and_Units/Time/">Yahoo!
Science > Measurements and Units > Time</a></li>
</ul>
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