What this source helps you find
Find civil-time rules, UTC offsets and daylight-saving changes in an identified tz database release.
Public sources / INT
IANA — Time Zone Database
Find civil-time rules, UTC offsets and daylight-saving changes in an identified tz database release.
Provenance and evidence type
- Operator or reference institution
- IANA · Time Zone Database
- Result type
- Research index or metadata
Open the work, its version and editorial status. A bibliographic record or citation identifies an object without validating its findings.
Limit to retain in your conclusion
A zone name is not a fixed offset. Rules depend on date and release; the database does not establish when an event occurred.
Useful search anchors
- Dataset / series code
- Version / revision
Fields to record when citing a result
- Dataset / series code
- Version / revision
- Event, publication and observation dates
- Method / definition
Evidence record to retain
Original text, IANA zone, explicit offset, precision, tz release and access date.
Check before drawing a conclusion
Distinguish calendar date from instant. A local time without an offset may be ambiguous or nonexistent at a clock change.
Access, download and API conditions depend on the service. Consult the official documentation and the resource terms.
Cross-check this source in a research route
Reconcile timestamps
Retain each observation’s original timestamp, role and offset before converting instants to UTC.
Capture or network-query time is not necessarily publication or content-modification time.
Compare sourcesUseful methods
- Assess a public dataset before reuse
- Compare public indicators without false equivalence
- Evidence and source register
Other sources in this family
Before export or reuse
- Coverage
- INT
- Identifiers to retain
- Dataset / series code · Version / revision · Event, publication and observation dates · Method / definition
Licence and rights
Inspect the exact resource and its terms. Being viewable does not authorise redistribution; retain the resource licence and restrictions instead of inferring them from the portal.
Date and version
Record consultation date, covered period, last update and version separately. For revised data, retain the file or exact extraction reference.
What object does the result describe?
- Result unit
- Civil-time rule for a zone and period
- Time reference to retain
- Observation period, file version and extraction date; read revisions and flags.
Documentation and access
The web page, export and API may differ in coverage or terms. Check pagination, filters, authentication, quotas and licence for the access method used.
What does -00:00 mean?
RFC 3339 uses it for an unknown local offset when UTC time is known. Preserve that status instead of treating it as evidence of a local zone.
How can a conversion be revisited after time-zone rules change?
Keep IANA zone, local date, chosen offset and tz version. Recalculation with another version may differ; retain both outputs and explain.
Normalise dates in a source dossier