The Time Zone Database (often called tz or zoneinfo ) contains code and data that represent the history of local time for many representative locations worldwide. It is updated periodically to reflect changes made by political bodies to time zone boundaries, UTC offsets, and daylight-saving rules.
The database is primarily intended for software implementers. Its data is expressed as machine-readable rules that, together with the reference implementation, allow software to automatically calculate local time with the correct UTC offset for any given location. End users typically receive updates to this data through their software and operating system vendors.
Latest version
2026c
Released
- Alberta moved to permanent -06 on 2026-06-18.
- Morocco moves to permanent +00 on 2026-09-20.
- More integer overflow bugs have been fixed in zic.
Learn more
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Release History
An index of all past releases of the Time Zone Database, with a summary of what changed and downloads for each.
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Contributing
How to propose changes to the database, subscribe to the mailing lists, and who coordinates the project.
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Sources and Links
An overview of the database with links to software, precompiled distributions, and related civil time resources.
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Theory and Pragmatics
The scope, principles and design decisions that guide how the database models civil time around the world.
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How to Read the Database
A guide to reading and interpreting the source files that make up the Time Zone Database.
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Time and the Arts
A lighter look at daylight saving time and time zones in film, music, literature and popular culture.