Sources & Licensing

All data presented on this website is derived from public authorities, public domain databases, and open data contributors.

1. The IANA Time Zone Database (tzdb)

The primary source for all civil offsets, daylight saving transitions, maintainer commentary, and version releases is the official IANA Time Zone Database maintained by Paul Eggert and the tz community:

Distribution repository: https://data.iana.org/time-zones/releases/
Source files parsed: africa, antarctica, asia, australasia, europe, northamerica, southamerica, etcetera, backward, backzone, zone1970.tab, zone.tab, iso3166.tab, leap-seconds.list, NEWS, theory.html, tz-link.html, and version.
Git mirror: https://github.com/eggert/tz

tzdb License Declaration

Unless specified below, all files in the tz code and data (including
this LICENSE file) are in the public domain.

If the files date.c, newstrftime.3, and strftime.c are present, they
contain material derived from BSD and use the BSD 3-clause license.

2. Time Zone Boundary Geometry

Zone boundary polygons are derived from the timezone-boundary-builder project created by Evan Siroky (https://github.com/evansiroky/timezone-boundary-builder), timezones-with-oceans release.

Because timezone-boundary-builder derives from OpenStreetMap, the geographic boundaries are licensed under the Open Database License (ODbL) by the OpenStreetMap Foundation (OSMF).

3. Country Boundaries and Graticules

Small-scale basemaps and fallback geometry derive from Natural Earth 1:110m public domain physical and cultural map datasets (https://www.naturalearthdata.com).

4. Country Names and Codes

All country names, common English designations, and ISO 3166-1 alpha-2 codes derive exclusively from iso3166.tab in the tzdb distribution. No third-party country tables or naming conventions are used.