What this is
World Timezones is a fast, no-account time zone converter. Add the cities and zones you care about, scrub through the day, and see day/night and working-hour bands across every row at the same time.
How it handles DST
Time math runs through the IANA Time Zone Database, so daylight saving transitions are picked up automatically on the right date in each zone. There is nothing to toggle — offsets shift when the rules say they shift, including spring-forward and fall-back edges within the day you are viewing.
Where the data comes from
- City list and coordinates: GeoNames, licensed under CC BY 4.0.
- Time zone rules: the IANA Time Zone Database.
- Sunrise and sunset: astronomical calculations from the SunCalc library, with sensible fallbacks at polar latitudes where the sun does not rise or set on a given day.
Contact
Bug reports, missing or wrong data (cities, zones, DST rules), privacy questions, or anything else: support@worldtimezones.net. Time zone data changes — countries adopt or drop DST, redraw boundaries, or rename zones — so corrections are always welcome.