The international standard reference time. It also corresponds to the local time at zero longitude. The standards pertaining to the definition and maintenance of Coordinated Universal Time, which effectively replaced Greenwich Mean Time (GMT) on 1 January 1972, are promulgated in Recommendation 460 of the International Consultative Committee for Radio (Comite Consultatif International de Radiodiffusion or CCIR) of the International Telecommunications Union. The CCIR is located at 2, rue de Varembe, 1211 Geneva 20, Switzerland. Responsibility for time standards in the United States rests with the Time and Frequency Division of the National Institute of Standards and Technology (NIST) in Boulder, Colorado.
Universal Time (which see).
Greenwich Mean Time updated with leap seconds
Globally used standard for time. UTC and GMT are essentially the same — both refer to time on the zero or Greenwich meridian. Bodies such as ICANN and WIPO often use universal time when referring to election dates and legal deadlines.
By international agreement, the local time at the prime meridian, which passes through Greenwich, England. Therefore, it is also known as Greenwich Mean Time, or sometimes simply Universal Time.
UTC is the official measurement of time throughout the world, independent of time zones.
The international time standard is called Coordinated Universal Time or, more commonly, UTC, for "Universal Time, Coordinated". This standard has been in effect since being decided on in 1972 by worldwide representatives within the International Telecommunication Union. UTC is maintained by the Bureau International de l'Heure (BIPM) which forms the basis of a coordinated dissemination of standard frequencies and time signals. The acronyms UTC and BIPM are each a compromise among all the participating nations.
Replaced Greenwich Mean Time (GMT) as the world standard for time in 1986. UTC uses atomic clock measurements to add or omit leap seconds each year to compensate for changes in the rotation of the earth.
International standard for measuring time of day.
The international standard of time, kept by atomic clocks around the world. Formerly known as Greenwich Mean Time (GMT), local time at zero degrees longitude at the Greenwich Observatory, England. UTC uses a 24-hour clock.
Same as Zulu (Z) and Greenwich Mean Time (GMT).
The international time standard. It is the current term for what was commonly referred to as Greenwich Meridian Time (GMT). Zero (0) hours UTC is midnight in Greenwich England, which lies on the zero longitudinal meridian. Universal time is based on a 24 hour clock, therefore, afternoon hours such as 4 p.m. UTC are expressed as 16:00 UTC (sixteen hours, zero minutes). Since a day is 24 hours long, the world may be split into 15 degree wide longitudinal bands (360 degrees/24 hours). Each band represents one hour. As an example, Huntsville Alabama is located at approximately 90 degrees west longitude, hence, local time lags UTC time by 6 hours (90/15, assuming Central Standard Time, 5 hours in Central Daylight Time). So, if the universal time is 14:30 UTC, United States Central Standard Time would be 8:30 am CST. http://www.ghcc.msfc.nasa.gov/utc.html
Replaced Greenwich Mean Time (GMT) as the World standard for time in 1986. It is based on atomic measurements rather than the earth's rotation. Greenwich Mean Time (GMT) is still the standard time zone for the Prime Meridian (Zero Longitude). It is the time kept by GPS satellites.
( UTC) Current official world time reference for civil and scientific purposes. Coordinated Universal Time is measured from six standard atomic clocks at the International Bureau of Weights and Measures ( BIPM) in Paris, France. Implemented in 1964.
Synonym for Greenwich Mean Time.
A time standard that is not affected by time zones or seasons. Time measured in coordinated universal time, labeled with the term zulu. It is used so that people around the world can communicate about time without regard to individual time zones.
Coordinated Universal Time (UTC - see Abbreviation below for explanation) is a high-precision atomic time standard. UTC has uniform seconds defined by International Atomic Time (TAI), with leap seconds announced at irregular intervals to compensate for the earth's slowing rotation, and other discrepancies. The leap seconds allow UTC to closely track Universal Time (UT), which is a time standard based on the earth's angular rotation, rather than a uniform passage of seconds.