UTC+00:00 is an identifier for a time offset from UTC of +00:00. This time zone is the basis of Coordinated Universal Time (UTC) and all other time zones are based on it. In ISO 8601, an example of the associated time would be written as 2069-01-01T12:12:34+00:00. It is also known by the following geographical or historical names:
a The islands of Cape Verde are to the west of the African mainland. bMauritius and the Seychelles are to the east and north-east of Madagascar respectively.
The westernmost point where UTC with DST is applied is El Hierro, Canary Islands, Spain (18°00′W). Time used there is 2 hours and 12 minutes ahead of physical time in the summer, making for the greatest discrepancy in the UTC time zone.
The easternmost settlement where UTC with DST is applied is LowestoftinSuffolk, East Anglia, UK (at just 1°45′E).
Morocco normally observes UTC+01:00, but the clock is set back one hour during Ramadan. See Time in Morocco for further information.
Whilst de facto Ireland operates on the same time as the United Kingdom, its de jure basis to do so differs. Whereas standard time in the UK is GMT in winter and BST (daylight saving time) in summer, Irish Standard Time (UTC+01:00) is observed in summer and GMT is used in winter. For details, see below.
As daylight saving time (Northern Hemisphere summer)
The westernmost point where UTC with no DST is applied is Bjargtangar, at the northwest peninsula of Iceland (24°32′W). Time used there is 1 hour and 38 minutes ahead of physical time. This is the greatest deviation from physical time for UTC+00:00 with no DST.
Discrepancies between use of UTC+00:00 as standard time rather than local solar time
Since legal, political, social and economic criteria, in addition to physical or geographical criteria, are used in the drawing of time zones, actual time zones do not precisely adhere to meridian lines. The UTC+00:00 time zone, were it determined purely by longitude, would consist of the area between meridians 7°30′W and 7°30′E. However, in much of Western and Central Europe, despite lying between those two meridians, UTC+01:00 is used; similarly, there are European areas that use UTC, even though their physical time zone is UTC−01:00 (e.g. most of Portugal), or UTC−02:00 (the westernmost part of Iceland). Because the UTC+00:00 time zone in Europe is at its western edge, Lowestoft in the United Kingdom, at only 1°45′E, is the easternmost settlement in Europe in which UTC+00:00 is applied.
Countries and areas west of 22°30′W ("physical" UTC−02:00) that use UTC+00:00
The westernmost part of Iceland, including the northwest peninsula (the Westfjords) and its main town of Ísafjörður, which is west of 22°30′W, uses UTC+00:00. Bjargtangar, Iceland is the westernmost point in which UTC is applied.
Countries and areas west of 7°30′W ("physical" UTC−01:00) that use UTC+00:00
Most of Portugal, including Lisbon, Porto, Braga, Aveiro, and Coimbra. (Only the easternmost part, including cities such as Bragança and Guarda, lies east of 7°30′W.) Madeira, at 17°W even further west, also employs UTC+00:00.
The western half of Ireland, including the cities of Cork, Limerick, and Galway
Extreme westerly portion of the Outer Hebrides, in the west of Scotland; for instance, Vatersay, an inhabited island and the westernmost settlement of Great Britain, lies at 7°54′W. If uninhabited islands or rocks are taken into account St Kilda, west of the Outer Hebrides, at 8°58′W, and Rockall, at 13°41′W, should be included.
Spain (except for the Canary Islands, which use UTC+00:00). Much of Galicia (and far western fringes of Extremadura and Andalusia) lie west of 7°30′W ("physical" UTC−01:00), whereas there is no Spanish territory that even approaches 7°30′E (the boundary of "physical" UTC+01:00). Spain's time is the direct result of Generalissimo Franco's presidential order (published in Boletín Oficial del Estado of 8 March 1940)[2] abandoning Greenwich Mean Time and advancing clocks one hour, effective from 23:00 on 16 March 1940. This is an excellent example of political criteria used in the drawing of time zones: the time change was passed "in consideration of the convenience from the national time marching in step according to that of other European countries".[3][4] The presidential order (most likely enacted to be in synchrony with Nazi Germany and Fascist Italy, with which the Franco regime was unofficially allied) included in its 5th article a provision for its future phase out,[4] which never took place. Due to this political decision, Spain is two hours ahead of its local mean time during the summer, one hour ahead in winter.[5]
Media related to UTC±00:00 at Wikimedia Commons