Skip to content


Subversion checkout URL

You can clone with
Download ZIP
Time zone database and code
C HTML Groff Makefile Shell Awk Perl
Failed to load latest commit information.
.gitignore * .gitignore: Ignore *.a files.
CONTRIBUTING * CONTRIBUTING: Prefer an https URL, as that's friendlier
Makefile Release tzcode2015g and tzdata2015g.
NEWS * NEWS: Mention last-minute localtime fix for Fiji.
README Reword so that it does not matter whether the word "data" is plural.
Theory North Korea changes to +0830 effective August 15
africa Revert previous change, about Morocco
antarctica Propagate Chile changes to Antarctica/Palmer
asctime.c Fix EOVERFLOW-related problems noted by Chistos Zoulas.
asia * asia (Azer): Update URL for 1997-03-17 Azeri resolution.
australasia Norfolk moves from +1130 to +1100 on 2015-10-04 at 02:00 local time.
backward Fix recently-introduced 'make check' failure
backzone Guess Cayman Is will observe DST starting 2016
checklinks.awk 'make check_links' now checks duplicate links etc.
checktab.awk Move one out-of-scope zone to 'backzone'
date.1 Port 'date' better to POSIX 1003.1-2001 and later
date.c Remove support for setting the date
difftime.c Avoid unnecessary casts in difftime
etcetera Simplify use of URLs in text files.
europe * europe: Add official announcement for Turkey change.
factory Simplify use of URLs in text files. Spell Åland etc. with accents in
leap-seconds.list No leap second on 2015-12-31.
leapseconds.awk * leapseconds.awk, NEWS: Also output expiration date comment.
localtime.c Fix signed 32-bit time_t localtime bug on Fiji
newctime.3 Add documentation for the core NetBSD-inspired functions.
newstrftime.3 Document thread-safe functions in man pages.
newtzset.3 Fiji observes DST from 2014-11-02 02:00 to 2015-01-18 03:00.
northamerica Fort Nelson has been on MST since 2015-03-08.
pacificnew Switch back to ASCII for symbols.
private.h Declare timezone, daylight, altzone in private.h
southamerica A few more instances of "No."
strftime.c Simplify strftime's use of tm_zone
systemv Simplify use of URLs in text files.
time2posix.3 Document thread-safe functions in man pages.
tz-art.htm Fix HTML typo
tz-link.htm * tz-link.htm: Use better URL for HTTP.
tzfile.5 Remove synopsis from tzfile man page
tzfile.h Use bool for boolean.
tzselect.8 Rename to
tzselect.ksh tzselect: port to POSIX sh and fix a typo Simplify use of URLs in text files. Distinguish hyphen from minus from dashes.
zdump.8 * zdump.8: Be more specific about when a year starts.
zdump.c Pacify Visual Studio 2013 'const' yet again
zic.8 Support %z in Zone formats
zic.c Fix sign of %z output, and add DST offset Fort Nelson has been on MST since 2015-03-08. Fort Nelson has been on MST since 2015-03-08. Rename fields of Link lines for clarity.


README for the tz distribution

"What time is it?" -- Richard Deacon as The King
"Any time you want it to be." -- Frank Baxter as The Scientist
					(from the Bell System film "About Time")

The Time Zone Database (often called tz or zoneinfo) 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 time zone boundaries, UTC offsets,
and daylight-saving rules.

Unless otherwise specified, all files in the tz code and data are in
the public domain, so clarified as of 2009-05-17 by Arthur David Olson.
The few exceptions are code derived from BSD, which uses the BSD license.

Here is a recipe for acquiring, building, installing, and testing the
tz distribution on a GNU/Linux or similar host.

	mkdir tz
	cd tz
	wget --retr-symlinks '*-latest.tar.gz'
	gzip -dc tzcode-latest.tar.gz | tar -xf -
	gzip -dc tzdata-latest.tar.gz | tar -xf -

Be sure to read the comments in "Makefile" and make any changes needed
to make things right for your system, especially if you are using some
platform other than GNU/Linux.  Then run the following commands,
substituting your desired installation directory for "$HOME/tzdir":

	make TOPDIR=$HOME/tzdir install
	$HOME/tzdir/etc/zdump -v America/Los_Angeles

Historical local time information has been included here to:

*	provide a compendium of data about the history of civil time
	that is useful even if not 100% accurate;

*	give an idea of the variety of local time rules that have
	existed in the past and thus an idea of the variety that may be
	expected in the future;

*	provide a test of the generality of the local time rule description

The information in the time zone data files is by no means authoritative;
fixes and enhancements are welcome.  Please see the file CONTRIBUTING
for details.

Thanks to these Time Zone Caballeros who've made major contributions to the
time conversion package: Keith Bostic; Bob Devine; Paul Eggert; Robert Elz;
Guy Harris; Mark Horton; John Mackin; and Bradley White.  Thanks also to
Michael Bloom, Art Neilson, Stephen Prince, John Sovereign, and Frank Wales
for testing work, and to Gwillim Law for checking local mean time data.
Thanks in particular to Arthur David Olson, the project's founder and first
maintainer, to whom the time zone community owes the greatest debt of all.
None of them are responsible for remaining errors.

Look in <> for updated versions of these files.

Please send comments or information to
Something went wrong with that request. Please try again.