Clockety · World Clocks tool · Time zones · About

How world clocks work

A world clock shows the current local time in one or more cities at once. Clockety’s interactive world clocks tool updates every second in your browser. This guide explains the ideas behind that display so the numbers make sense even if a widget is slow to load.

What a world clock actually shows

Every city clock is “now” expressed in that city’s time zone. The underlying instant is the same everywhere—UTC time progresses uniformly—but legal civil time differs by offset. When New York is on UTC−4 and Tokyo is on UTC+9, the clocks differ by thirteen hours even though both are correct for the same moment.

IANA time zones

Modern browsers ship the IANA time-zone database (often called tzdata). Identifiers look like America/New_York or Asia/Tokyo. They encode historical and future offset rules, including daylight saving transitions. Clockety relies on that database rather than inventing offsets.

Tips for remote teams

Related tools and guides

Open the world clocks tool, convert with the time zone converter, or read how time zones work. Return to the Clockety homepage for the full overview.

FAQ

Do world clocks need an internet connection after load?

Once the page and zone data are available in the browser, the clock advances from your device time. A live connection is still useful for loading the page and receiving software updates.

Why did a city jump by one hour overnight?

That usually means a daylight saving transition in that zone. Confirm on the time zone info page or an official source for that region.