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Time zone rules are set by governments and change more often than most people realize. This policy documents how DateAndTimePro.com sources, maintains, and presents time zone information.
Time zone databases
- Time zone calculations are powered by widely adopted public time zone databases (such as the IANA Time Zone Database) as integrated into our runtime and supported by browsers.
- Where helpful, we also reference country-level metadata to label cities, regions, and abbreviations.
UTC offsets
- Every supported zone is represented by its current UTC offset and, where applicable, its daylight saving offset.
- Conversions occur in UTC internally and are formatted for display in the target zone.
Governmental and historical changes
- When a government announces a change to a time zone, daylight saving rule, or jurisdictional boundary, that change is reflected once it has been incorporated into the public time zone database we rely on.
- Historical conversions reflect the rules in effect at the historical instant where the underlying database supports it.
Update policy
- We track updates to the underlying time zone database and roll forward as they are published.
- Material changes that affect popular calculators or city hubs are noted on the affected pages.
Important limitation
Time zone rules are subject to change. Future offsets reflect the rules currently known to legislators and database maintainers and may be revised. For legal, travel, broadcast, or contractual decisions, verify the applicable time zone with an authoritative governmental source.
Published by Relationale LLC, founded by Keiron Brown. For questions about this document, see our Contact page or browse the Time Intelligence Trust Center.