timezonefinder-data

The timezone boundary data used by timezonefinder, compiled from timezone-boundary-builder releases into the binary format described in the data format reference.

pip install timezonefinder installs this package automatically - there is nothing extra to do. It is a separate distribution so that a new boundary release can ship without a timezonefinder release, and so that a deployment can pin the dataset its answers came from:

pip install "timezonefinder-data==3.2026.3.post1"

The version reads <format>.<year>.<letter>[.postN]: the year and numbered letter name the timezone-boundary-builder release (2026c -> 2026.3), and the major is the binary data format generation. A .postN suffix identifies revised compiled data made from the same upstream release. timezonefinder requires a data version inside the format generation it can read, so an ordinary data update needs no code release while a format change is refused by the resolver instead of at the first lookup.

Releases

• 4.2026.5 - timezone-boundary-builder 2026e, 2026-10-18 - Updated the packaged boundaries to upstream 2026e and introduced data format 4: a longitude/latitude-aligned grid tree of 0.75° cells, refined into 4×4 blocks where zones meet, replacing the H3 index.
• 3.2026.4 - timezone-boundary-builder 2026d, 2026-09-21 - Updated the packaged boundaries to upstream 2026d.
• 3.2026.3.post1 - timezone-boundary-builder 2026c, 2026-09-10 - Recompiled shortcut candidates in estimated full-lookup work order.
• 3.2026.3 - timezone-boundary-builder 2026c, 2026-09-02 - Introduced shortcut format 3 with conservative polygon-cell overlap coverage.
• 2.2026.3 - timezone-boundary-builder 2026c, 2026-08-23 - Added latitude-block indexes and packed coordinate payloads.
• 1.2026.3 - timezone-boundary-builder 2026c, 2026-08-18 - First standalone data distribution.

License

The boundary data is licensed under the Open Database License (ODbL), see DATA_LICENSE. The timezonefinder source code is MIT licensed.