Standard time in the context of "UTC offset"

A time zone is an area which observes a uniform standard time for legal, commercial and social purposes. Time zones tend to follow the boundaries between countries and their subdivisions instead of strictly following longitude, because it is convenient for areas in frequent communication to keep the same time.

Each time zone is defined by a standard offset from Coordinated Universal Time (UTC). The offsets range from UTC−12:00 to UTC+14:00, and are usually a whole number of hours, but a few zones are offset by an additional 30 or 45 minutes, such as in India and Nepal. Some areas in a time zone may use a different offset for part of the year, typically one hour ahead during spring and summer, a practice known as daylight saving time (DST).

Decimal time is the representation of the time of day using units which are decimally related. This term is often used specifically to refer to the French Republican calendar time system used from 1794 to 1800, during the French Revolution, which divided the day into 10 decimal hours, each decimal hour into 100 decimal minutes and each decimal minute into 100 decimal seconds (100,000 decimal seconds per day), as opposed to the more familiar standard time, which divides the day into 24 hours, each hour into 60 minutes and each minute into 60 seconds (86,400 SI seconds per day).

The main advantage of a decimal time system is that, since the base used to divide the time is the same as the one used to represent it, the representation of hours, minutes and seconds can be handled as a unified value. Therefore, it becomes simpler to interpret a timestamp and to perform conversions. For instance, 12345 is 1 decimal hour, 23 decimal minutes, and 45 decimal seconds, or 1.2345 decimal hours, or 123.45 decimal minutes or 12345 decimal seconds; 3 hours is 300 minutes or 30,000 seconds.This property also makes it straightforward to represent a timestamp as a fractional day, so that 2025-12-02.54321 can be interpreted as five decimal hours, 43 decimal minutes and 21 decimal seconds after the start of that day, or a fraction of 0.54321 (54.321%) through that day (which is shortly after traditional 13:00). It also adjusts well to digital time representation using epochs, in that the internal time representation can be used directly both for computation and for user-facing display.

Central European Time (CET) is a standard time observed in Central as well as parts of Western and Southeast Europe, which is one hour ahead of Coordinated Universal Time (UTC). The time offset from UTC can be written as UTC+01:00. It covers most of continental Europe and it has been adopted by several African countries where it is known under various other names.

CET is also known as Middle European Time (MET, German: MEZ) and by colloquial names that reference major European cities such as Amsterdam Time, Berlin Time, Brussels Time, Budapest Time, Madrid Time, Paris Time, Stockholm Time, Rome Time, Prague time, Warsaw Time or Romance Standard Time (RST).

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. UTC is calculated by reference to atomic clocks and was adopted in 1972. Older systems use telescope observations.

In traditional astronomical usage, civil time was mean solar time reckoned from midnight. Before 1925, the astronomical time 00:00:00 meant noon, twelve hours after the civil time 00:00:00 which meant midnight. HM Nautical Almanac Office in the United Kingdom used Greenwich Mean Time (GMT) for both conventions, leading to ambiguity, whereas the Nautical Almanac Office at the United States Naval Observatory used GMT for the pre-1925 convention and Greenwich Civil Time (GCT) for the post-1924 convention until 1952. In 1928, the International Astronomical Union introduced the term Universal Time for GMT beginning at midnight.

Local time is the time observed in a specific locality. There is no canonical definition. Originally it was mean solar time, but since the introduction of time zones it is generally the time as determined by the time zone in effect, with daylight saving time where and when applicable. In some places this is known as standard time.

Some sources continue to use the term local time to mean solar time as opposed to standard time, but they are in the minority. Terms such as local mean time also relate to solar time.

Daylight saving time (DST), also referred to as daylight savings time, daylight time (United States and Canada), or summer time (United Kingdom, European Union, and others), is the practice of advancing clocks to make better use of the longer daylight available during summer so that darkness falls at a later clock time. The standard implementation of DST is to set clocks forward by one hour in spring or late winter, and to set clocks back by one hour to standard time in the autumn (or fall in North American English, hence the mnemonic: "spring forward and fall back").

In several countries, the number of weeks when DST is observed is much longer than the number devoted to standard time.

Eastern Indonesia (or East Indonesia; Indonesian: Indonesia Timur, pronounced [ɪndoˌnes(i)ja ˈt̪imʊr]) is one of the two main geographical regions of Indonesia, the other being Western Indonesia. It comprises four geographical units: Lesser Sunda Islands, Sulawesi, Maluku Islands and Papua. Central Indonesian Time and Eastern Indonesia Time are the national standard time designated for Eastern Indonesia; it falls within the UTC+8 and UTC+9 time zone, respectively.

Eastern Indonesia borders the Southern Philippines and Palau in the North, Papua New Guinea in the East, and Northern Australia in the South.

Eastern European Time (EET) is one of the names of the UTC+02:00 time zone, 2 hours ahead of Coordinated Universal Time. The zone uses daylight saving time, so that it uses UTC+03:00 during the summer.

A number of African countries use UTC+02:00 all year long, where it is called Central Africa Time (CAT), although Egypt and Libya also use the term Eastern European Time.

Africa, the world's second-largest and second-most populous continent, spans across six different time zone offsets from Coordinated Universal Time (UTC): UTC−01:00 to UTC+04:00. As Africa straddles the equator and tropics, there is little change in daylight hours throughout the year and as such daylight saving time is currently observed in only two countries, Morocco (year-round except Ramadan) and Egypt. However, it was previously observed in several other countries.

Before the wide adoption of standard time zones, local mean time was widely used in railway time for train timetables and telegraphic time for telegraphy. Local mean time is a solar time that corrects the variations of local apparent time by forming a uniform time scale at a specific longitude; for instance, Liberia observed UTC−0:44:30 instead of an approximate offset such as UTC−01:00. British Rhodesia (at the time administered by the private British South Africa Company) was the first area in Africa to adopt standard time, switching to UTC+02:30 on 1 August 1899 as the previous time standards proved problematic for the railway system. Other countries followed suit, and by 1912, most Portuguese, French and British territories had adopted a standard offset. Liberia was the last country in Africa to adopt a standard offset, doing so on 7 January 1972.