World Clock: Frequently Asked Questions

Up to 6 cities simultaneously. The layout adapts to show all cities clearly. For comparing more than 6 cities, run two separate comparisons, or use the 24-hour grid which shows all selected cities together.

Yes. The clock uses the browser's Intl.DateTimeFormat API with IANA time zone names, which automatically applies the correct DST offset for every city based on the current date. No manual adjustment is ever needed.

The green sun icon indicates the city is currently in business hours (9am–6pm local time). A moon icon indicates night time (10pm–6am). No icon means the city is in its 'shoulder' hours outside both windows.

Cities to the east of you in the next calendar day will show tomorrow's date; cities far to the west may show yesterday's. This is a real difference — a meeting 'on Tuesday' means different calendar dates depending on each person's location relative to the international date line.

UTC (Coordinated Universal Time) is the primary global time standard. All time zones are expressed as UTC offsets. UTC does not observe daylight saving time, making it the unambiguous reference point for international scheduling and technical systems.

City selections are maintained for the current session. For a persistent setup, bookmark the page and re-select your cities — the selection process takes under 30 seconds. Future versions may save preferences in browser localStorage.