Greenwich Mean Time

E3109

civil time standard time standard time zone

Greenwich Mean Time is the mean solar time at the Royal Observatory in Greenwich, London, historically used as the world’s primary reference for timekeeping and the basis for Coordinated Universal Time (UTC).

Aliases (5)

Statements (47)

Predicate	Object
instanceOf	civil time standard → time standard → time zone →
abbreviation	GMT →
associatedWith	Prime Meridian → longitude 0° →
basisFor	Coordinated Universal Time → UTC offset system →
category	astronomy → navigation → timekeeping →
coordinateReference	0 hours offset baseline →
coordinateSystemRole	reference for global time zones →
definedAs	mean solar time at the Royal Observatory, Greenwich →
definedRelativeTo	Earth rotation →
governingBody	Royal Observatory, Greenwich →
hasAlternativeName	GMT → Greenwich time →
historicalRole	basis for international civil time → world primary reference for timekeeping →
language	English term →
measurementType	mean solar time →
notSameAs	local apparent solar time at Greenwich →
observesDaylightSaving	false →
offsetRange	+00:00 year-round →
referenceCity	London →
referenceCountry	United Kingdom →
referenceLocation	Royal Observatory, Greenwich →
relatedStandard	International Atomic Time →
relatedTo	British Summer Time → UT1 → Universal Time →
replacedBy	Coordinated Universal Time →
standardizedAt	International Meridian Conference →
standardizedInYear	1884 →
supersededInPrecisionBy	atomic time →
timeOffsetFromUTC	UTC+00:00 →
usedAs	prime meridian time standard →
usedAsLegalTime	true in some jurisdictions →
usedIn	Iceland → Ireland (winter) → Portugal (mainland, winter) → United Kingdom (winter) → West Africa (some countries) → some Atlantic islands →
usedInAviation	yes (historically, now largely UTC) →
usedInMaritimeNavigation	yes →

Referenced by (254)

Subject (surface form when different)	Predicate
Aberdeen → Accra → Albufeira ("Western European Time") → Alternative Investment Market → Ash, Devon → BR2 → Banjul → Bath, Somerset, England → Bedfordshire → Berkshire → Blackheath, London, England → Bootle → Borough of Halton → Bradford → Buckinghamshire → Cambridge, England → Cambridgeshire → Camden → Cathedral Quarter → Central England → Central Scotland → Ceredigion → Charlton, Hertfordshire, England → Cheshire → City of Westminster → City of York → Cliad → Coatbridge → County Antrim → County Durham → Craven → Derbyshire → Douglas → Downe → Dublin → East Riding of Yorkshire → East of England → Edinburgh → Elizabeth Tower → Elm → Elmbridge → England → Freetown → Gifford, East Lothian, Scotland → Glasgow City → Gloucester → Gloucestershire → Great Britain → Greater Accra Region → Greater London → Greater Manchester → Guéckédou Prefecture → Hale Barns → Halton → Hart District → Haslingden → Herefordshire → Hillsborough, County Down → Holborn, London, England → Holt Town → Inner London → Keston → Lambeth → Leeds → Liverpool → London → London Borough of Lewisham → London Borough of Wandsworth → Luton → Malvern → Manchester → Meliandou → Merseyside → Metropolitan Borough of Bury → Midlands → Monrovia → Newark-on-Trent → Newcastle upon Tyne → Norfolk → North East England → North East Lincolnshire → North Yorkshire → Northern England → Northern Ireland → Oldham borough → Ouagadougou → Oxfordshire → Perth → Peterborough (unitary authority) → Plymouth → Port Talbot → Putney → Reddish → Richmond → Rochford District → Royal Borough of Greenwich → Rutland → Sidcup → Sierra Leone → Somers Town, London, England → Somerset → South East England → South Gloucestershire → South Yorkshire → Southwark → Southwest England → Spitalfields → St Helens → Staffordshire → Stockport → Surrey → Surrey Heath → Tameside → Test Valley district → Torfaen → Tyne and Wear → United Kingdom → Vale of Glamorgan → Wakefield → Wales → Warrington → West Berkshire → West Midlands → Westminster, London, England → Wigan → Winchester → Wirral → Wootton → Yorkshire and the Humber →	timeZone
Addlestone → Admiralty (United Kingdom) → Ascott → BT Group → Bath and North East Somerset Council → Benchill → Bracknell Forest → British Home Department → Brookeborough, County Fermanagh, Ireland → Butt Lane, Staffordshire → Cambridgeshire County Council → Carnegie, Angus → Central London → City of Edinburgh council area → City of London → Conakry → Department for Work and Pensions → Douglas, Isle of Man → East Kilbride → Eltham Palace → Fawler → Fishguard → HM Treasury → HM Treasury → Hale → Hayes → His Majesty's Passport Office → Hulme, Manchester → Institution of Civil Engineers → Killingholme → Knowsley → Leytonstone → Lord Lieutenant of Hampshire → Lord Mayor of London → Merthyr Tydfil County Borough Council → Metropolitan Borough of Manchester → Ministry of Information (United Kingdom) → Northern Ireland Prison Service → Northern Quarter → Norton → Outer London → Parole Board for England and Wales → Penge → Pentonville → Prime Minister's Office (United Kingdom) → Queen's Square, Belfast → Sale → South Lanarkshire → South Wales → Southern England → Stevenage → Sutton → Swansea → UK Debt Management Office → United Kingdom Ministry of Defence → West Gorton → West London → Wolverhampton → Woolwich → York →	locatedInTimeZone
Bagshot → Broadstairs → Clackmannanshire → Clayton → Cowdenbeath → Eton, Berkshire → Gaywood → Glasgow → Halifax → Hethel, Norfolk, United Kingdom → Kew → Killingworth → Ladbroke Grove → Marshland St James → Porthmadog → Ramsgate → Roundthorn → Stow Bardolph →	observes
Dorset → East Sussex → Shropshire → West Sussex → West Yorkshire →	hasTimeZone
Clifton → Crail → Isleworth, Middlesex, England → Seething Lane →	observesTime
Coordinated Universal Time → Greenwich Mean Time ("Universal Time") → International Date Line → Zulu time →	relatedTo
Greenwich → Greenwich, Kent, England → Maritime Greenwich →	knownFor
BST → British Summer Time → Prime Meridian →	relatedConcept
Irish Standard Time ("Greenwich Mean Time (when GMT is UTC+0)") → Western European Summer Time ("Greenwich Mean Time (when GMT is used as winter time)") →	isOneHourAheadOf
Delly End → Nottinghamshire →	usesTimeZone
GMT →	abbreviationOf
Greenwich Park →	associatedWith
British Summer Time →	basedOnTimeZone
International Meridian Conference →	definedConcept
British Summer Time →	followedByTimeZone
British Summer Time →	followsTimeZone
GMT →	fullName
BST →	hasOppositeTime
Irish Standard Time →	isDaylightSavingFor
NST →	isWestOf
St John’s →	observesTimeZone
North American time zones ("International Meridian Conference of 1884") →	partlyDefinedBy
Prime Meridian →	referenceFor
Pakistan Standard Time →	relatedStandard
British Summer Time Act 1972 →	relatesTo
Europe/London →	standardTimeName
Coordinated Universal Time →	successorOf
Greenwich →	timeStandard
Western Hemisphere →	timeStandardReference
West Africa →	timeZoneIncludes
Greenwich, Kent, England →	timeZoneReference
BST →	usedWithStandardTime
Europe/London →	usesInWinter
British Summer Time Act 1972 →	usesTimeStandard