<Tr> <Td> 21: 49, 30 October 2018 UTC (refresh) </Td> </Tr> <P> Coordinated Universal Time (abbreviated to UTC) is the primary time standard by which the world regulates clocks and time . It is within about 1 second of mean solar time at 0 ° longitude, and is not adjusted for daylight saving time . In some countries where English is spoken, the term Greenwich Mean Time (GMT) is often used as a synonym for UTC . </P> <P> The first Coordinated Universal Time was informally adopted on 1 January 1960 and was first officially adopted as CCIR Recommendation 374, Standard - Frequency and Time - Signal Emissions, in 1963, but the official abbreviation of UTC and the official English name of Coordinated Universal Time (along with the French equivalent) were not adopted until 1967 . </P> <P> The system has been adjusted several times, including a brief period where time coordination radio signals broadcast both UTC and "Stepped Atomic Time (SAT)" before a new UTC was adopted in 1970 and implemented in 1972 . This change also adopted leap seconds to simplify future adjustments . This CCIR Recommendation 460 "stated that (a) carrier frequencies and time intervals should be maintained constant and should correspond to the definition of the SI second; (b) step adjustments, when necessary, should be exactly 1 s to maintain approximate agreement with Universal Time (UT); and (c) standard signals should contain information on the difference between UTC and UT ." </P>

Coordinated universal time is the present name for world standard time