Why are times different in other countries?

Clocks in other countries need to be adjusted so that it gets light and dark at approximately the same time everywhere. Without this adjustment, people might find that dawn was at 10 o'clock in the evening, for example.

In 1884 time zones were set up around the world, measured from Greenwich in London, England. Every time zone east or west of Greenwich has noon at a different time. Each zone is either one hour ahead or behind of its neighbouring zone -- it is one hour earlier to the west of each zone, and one hour later to the east.