Introduction to time zones

Time zones are regions of the Earth that have the same standard time. They were created to facilitate communication and travel across different regions of the world.

How do time zones work?

The concept of time zones is based on the fact that the Earth completes a full rotation on itself in 24 hours. Thus, the planet is divided into 24 time zones, each representing one hour of the day.


UTC (Coordinated Universal Time) and GMT (Greenwich Mean Time) are often used as a reference for time zones. UTC is a time scale based on the atomic clock, while GMT is based on solar observation in Greenwich, England.

Time Zone Changes

Traveling from east to west or vice versa, one crosses different time zones. This can impact our perception of time, a phenomenon often called jet lag.

Daylight Saving Time

Some countries adopt daylight saving time, advancing their clocks by one hour for part of the year. This is done to make better use of natural light during summer evenings.