International Time

The map also provides answers to questions: Where is it day, evening or middle of the day? Co-ordinated Universal Time (UTC) is the foundation of our contemporary civilian life. From January 1, 1972, it has been specified to track the International Atomic Time (TAI) with an accurate shift of a whole number of seconds, which only changes when a leak second is added to synchronize the watches with the Earth's orbit.

The Greenwich Mean Time (GMT) is an older norm that was introduced on UK railways in 1847. With the help of a telescope instead of an astronomical clock, the GMT at the Royal Observatory in Greenwich was tuned to mean sun time. The Universal Time (UT) is the advanced name for the international telescope-based system introduced by the International Astronomical Union in 1928 to substitute Greenwich Mean Time.

Greenwich Observatory itself was discontinued in 1954, although the site is still used as the base for the co-ordinate system. Since the Earth's rotation time is not completely consistent, the length of a second would change if it were tuned to a telescope-based calibration such as GMT or UT - in which a second was measured as a split of a whole year or a whole days.

GMT " and "Greenwich Mean Time" are sometimes used as informal words to describe how GMT refers to time. World is divided into a number of time zones. Exactly one half of the time zone is between most time zones and their local time is calculated conventionally as an off-set to either GMT or ATC. Time zone is a geographically defined area of the planet that is more or less limited by longitudes and has a single, statutory default time, commonly known as local time.

Conventionally, the 24 major time zones on Earth calculate their local time as an off-set of UnTC, with each time zone border allegedly 15 deg due either East or West of the previous. Greenwich meridian (the prime meridian), which has a meridian of 0°, is the datum point for ATC. The local time is ATC plus the actual time zone shift for each site.

The corresponding one-hour decline from normal levels to 15° is observed every 15 from the west border of the time zone to the International Date Line. Also known as "summer time", it is the practical time to advance watches momentarily so that the afternoon has more light and the morning less.

Typically, in a case where a one-hour layer takes place at 02:00 local time, in early Spring the watch will jump from 02:00 local time to 03:00 local time and that date will have 23 consecutive working time, while in early Fall the watch will jump backwards from 02:00 local time to 01:00 local time and repeat that particular working time and that particular date will have 25 consecutive working time.

Rather than reading exactly 02:00 during a shiftshift, a digitally displayed locale time will jump from 01:59:59:59. This example shows a site that observes UTC+2 during daylight savings time at UTC+3 during daylight savings time; vice versa a site at UTC-5 during daylight savings time at UTC-4 during daylight savings time. Weltuhr und Zeitzonen-Karte online - Current time in every county and every metropolis around the world.