So-called Standard Time is a scale based on Coordinated Universal Time and is determined by measuring the distance east or west of Greenwich, England.
The Earth is divided into 24 areas cut off by meridians of latitude which are distributed 15 degrees apart in time and distance. The 24 areas are defined by one complete rotation of the Earth, and correspond to 24 time zones extending from pole to pole.
Adjacent time zones are one hour apart.
The Standard Time scale is used as the measure for all international time standards.
Some slight variations occur in International Legal Time when a country extending across more than one time zone maintains a national uniform time.