The world time zone map uses a repeating color scheme to designate the different standard time zones observed in each country. Most countries do not adjust their time zone observance and when they do it most likely involves small boundary changes or changes in the observance of daylight saving time. The world time zone map indicates the standard time zones actually observed. In theory time zones are based on the division of the world into twenty four time zones of 15 degrees longitude each. The time convention begins with Universal Coordinated Time (UTC) which is also commonly referred to as Greenwich Mean Time (GMT) being located at the Greenwich meridian. This line runs through the United Kingdom, France, Spain, Algeria, Mali and Ghana in Africa. The Greenwich meridian time zone is 7/12 degrees east and 7/12 degrees west of zero degrees longitude. Time zones to the east of the Greenwich meridian are later and times to the west of the Greenwich meridian are earlier. To see more detail view our larger format world time zone map.
This world time zone map shows the division of the world into twenty four time zones of 15 degrees longitude each. However, if you compare this theoretical system with actual time usage throughout the world, you will see there are many variations in how countries actually observe time zones. The reasons for this vary but include commerce and transportation.