The Global Clock prefers standards bodies, government scientific agencies, specifications, and primary documentation. These links explain the rules and methods behind the site; the visitor's browser remains the immediate runtime source for live civil-time conversion.
- IANA Time Zone DatabaseCanonical identifiers and periodically updated history of UTC offsets, boundaries, and daylight-saving rules.
- IANA time-zone and DST resourcesBackground on tzdb, implementations, civil-time concepts, and supporting references.
- ECMAScript Internationalization API specificationThe normative specification for JavaScript international date and time formatting.
- MDN: Intl.DateTimeFormatImplementation-oriented documentation for the browser API used to format instants in named time zones.
- NOAA sunrise and sunset equationsThe solar equations and standard 90.833° sunrise/sunset zenith referenced by the site's browser-side approximation.
- W3C WAI-ARIA specificationAccessibility semantics used alongside native HTML structure.
- Google Search Central: structured dataGuidance for meaningful, visible, page-relevant structured data. Markup can aid understanding but does not guarantee a rich result.
City coordinates and descriptive fields
City pages use a maintained local dataset of representative city names, countries, coordinates, and IANA identifiers. Coordinates are rounded representative points suitable for a city-level solar estimate; they are not survey-grade locations. Corrections should include an authoritative municipal, national, or standards-based reference.
Source review
Links and descriptions are reviewed when the methodology changes or a correction identifies a material issue. A source appearing here does not imply endorsement of The Global Clock by that organization.