Check browser timezone rules against IANA 2026e samples and understand ZoneMeetup’s city, holiday and locale data.
Check your browser’s time rules
IANA reference: 2026e, released 29 September 2026. This check uses offsets compiled from the original IANA release at eight dates in 2026–2028.
The browser API does not disclose its exact tzdata version. A match is not proof of complete coverage. The scheduling engine still uses browser rules; this reference check does not replace them.
Sources, scope and refresh
IANA Time Zone Database · Public-domain timezone data. Sample reference 2026e, retrieved 4 Oct 2026. Update your browser/OS for runtime rules; site maintainers refresh the pinned archive and rerun checks.
GeoNames cities500 · CC BY 4.0 · 235,917 places across 246 country codes. Snapshot 4 Oct 2026. Names, administrative codes, population and IANA zone IDs. Loaded only for the selected country. Alternate Arabic-script names are search aliases, not verified Arabic translations.
Unicode CLDR 48.2 · Unicode License v3 · English/Arabic territory names and suggested weekend conventions. Browser number/date formatting can use a different CLDR version.
Vacanza / Python holidays 0.105 · MIT · Generated community rules for 251 country codes and 879 national/subdivision choices, 2025–2030. Not an official live feed.
A region can change its offset with daylight saving or legislation. IANA zone IDs identify a rule history; country names and abbreviations do not. Kathmandu uses +05:45, Kolkata +05:30, and Lord Howe can change by half an hour. The meeting planner checks nonexistent and repeated local times and asks you to choose an occurrence for repeated times.
Keep future plans reviewable
Calendar exports use fixed UTC starts. A later legal timezone change will not rewrite an already downloaded event. Recheck future meetings after changes and regenerate the file when needed.
