Last updated this release
DateAndTimePro.com is built on widely adopted public standards and reference data. This page summarizes the categories of sources we rely on, how often they are refreshed, and the limitations users should keep in mind.
Categories of sources
- Public time and date standards — including ISO 8601 date and time formatting and the public IANA Time Zone Database as integrated by our runtime and browsers.
- Governmental publications — used as reference for time zone changes, daylight saving rules, and recognized national holidays.
- International standards bodies — including ISO and similar organizations for date, time, and calendar conventions.
- Publicly available reference data — such as country and city metadata used to label and group locations.
Update frequency
- Standards-based logic (date arithmetic, ISO formatting, week numbering) changes infrequently and is reviewed on each major release.
- Time zone and daylight saving rules are refreshed as upstream databases publish updates.
- Holiday and reference content is reviewed at least annually and when material changes become public.
Limitations
- Upstream sources may themselves contain inaccuracies, gaps, or delays in reflecting governmental changes.
- Future-dated rules (DST changes, holiday declarations, calendar reforms) cannot be predicted with certainty.
- Country, state, province, and municipality-level variation in observance may not be fully reflected on every page.
Reporting source issues
If you believe a data source on DateAndTimePro is out of date or incorrect, please use our Corrections Policy to let us know.
Published by Relationale LLC, founded by Keiron Brown. For questions about this document, see our Contact page or browse the Time Intelligence Trust Center.