World Time Zones
The world is divided into several time zones. Most time zones are exactly one hour apart and traditionally calculate their local time as a difference from UTC or GMT. In many places, these offsets change twice a year due to DST transitions.
However, each country may have a certain standard time zone if the world is more suitable for cooperation. A standard time zone is a region where local or national authorities unite time for a specific purpose. Time zones follow certain rules about longitude.