Why is GMT called Greenwich Mean Time

Greenwich Mean Time (GMT)

Countries in Greenwich Mean Time




GMT and UTC - Coordinated Universal Time

The differences between the individual time zones are always given in relation to the "Universal Time Coordinated" (UTC), i.e. the time that exists on the prime meridian (zero degree of longitude). Germany itself is in the UTC +1 time zone. The time zone UTC +0 applies for Greenwich Mean Time.

Greenwich Mean Time corresponds to the UTC 0 time zone, i.e. the Coordinated Universal Time with a 0 hour offset. Essentially, it corresponds to Western European Time, which is used in Portugal, for example, but is officially referred to as GMT in the United Kingdom and several African countries. The different designation of the same time zone often leads to confusion. GMT is the name of the time zone, while UTC is more of a name for a time system that also has its normal state on the prime meridian.

Origin of Greenwich Mean Time

During seafaring times, there were different zero meridians and systems for calculating positions, depending on the nation. One of the best known was based on the Greenwich meridian back then. It was not until 1884 that a globally standardized time system was agreed that divided the globe into 24 equal areas according to its longitude. Each segment of 15 ° corresponded to one hour, which in theory at least resulted in 24 uniformly sized time zones. With the establishment of the date line in an area between Asia and America that was as unpopulated as possible, the prime meridian was established on the opposite side of the globe in Greenwich. It was only with this globally standardized regulation that the coordinates we are given today were created. Numerous coordinate systems previously competed with one another.

In the courtyard of the historic Royal Greenwich Observatory, a brass strip and a laser beam now symbolize the prime meridian. However, the geographically correct position is about 100 meters further east.

Other countries with the same time UTC +0

Even if the time zone is called "Greenwich Mean Time", this has more political reasons and only means that, for example, the beginning and end of daylight saving time always apply uniformly here. There are certainly other countries where the clock is striking the same hour. These countries are summarized with the time difference to UTC (i.e. Universal Time Coordinated):