Time zones are areas on Earth that have the same time. Use this tag if you have problems setting up your `timezone` in Ubuntu.
The Earth is divided into 24 time zones - each with it's own time. Every time zone theoretically occupies 15° of the Earth's longitude, although, in practice, time zones vary due to country borders.
The times for the time zones are based on the Universal Coordinated Time (UTC, which used to be called Greenwich Mean Time, GMT).
Every time zone to the east of Greenwich,UK adds 1 hour to UTC, and every time zone to the west 1 hour from UTC.