In modern usage, civil time refers to statutory time as designated by civilian authorities. Modern civil time is generally national standard time in a time zone at a fixed offset from Coordinated Universal Time (UTC), possibly adjusted by daylight saving time during part of the year.

Legally, the civil time used in the UK is called "Greenwich mean time" (without capitalisation), with an exception made for those periods when the Summer Time Act 1972 orders an hour's shift for daylight saving.

2025年1月19日 · Greenwich Mean Time (GMT), the name for mean solar time of the longitude (0°) of the Royal Greenwich Observatory in England. The meridian at this longitude is called the prime meridian or Greenwich meridian. Greenwich Mean Time (GMT) has been used to clearly designate epoch by avoiding confusing references to local time systems (zones).

The GMT framework, set at the Prime Meridian (0° longitude), was based on the mean solar time at the Royal Observatory in Greenwich. The term 'GMT' gradually became synonymous with the time zone UTC+00:00 and formed the legal basis for civil time in the UK.

The worldwide timekeeping convention, known as Universal Time Coordinated (UTC), is often still colloquially referred to by its historical name, Greenwich Mean Time. But how did Greenwich, a borough in southeast London, become the reference point for timekeeping all around the world?

Discover how the Royal Observatory revolutionised the recording of world time, stand astride the Prime Meridian Line – the historic place where east meets west – and have a peek inside the …

Greenwich mean time or Greenwich meridian time (GMT), the former name for mean solar time at the site of the Royal Observatory in Greenwich, England, which is located on the prime meridian. In 1925 the numbering system was changed to make GMT equivalent

2025年1月13日 · In 1928, the International Astronomical Union recommended that the time used in the compilation of astronomical almanacs, essentially GMT, or what was also sometimes called Greenwich Civil Time, be referred to as Universal Time (UT).

2016年5月4日 · GMT stands for Greenwich Mean Time (also called Meridian Time or Zulu Time) and it is a time standard since 1884. It was chosen because the Prime Meridian (the line of 0° Longitude) runs through Greenwich.

ly’ named as ‘Greenwich Civil Time’ (GCT). However, as the abbreviation GCT was a military term, ‘Greenwich Civil ime’ was objected to by the British Admiralty. Because of this objection, …