A century is a period of 100 years. Centuries are numbered ordinally in English and many other languages. The word century comes from the Latin centum, meaning one hundred. Century is sometimes abbreviated as c.
A calendar date is a reference to a particular day represented within a calendar system. The calendar date allows the specific day to be identified. The number of days between two dates may be calculated. For example, "25 February 2024" is ten days after "15 February 2024". The date of a particular event depends on the observed time zone. For example, the air attack on Pearl Harbor that began at 7:48 a.m. Hawaiian time on 7 December 1941 took place at 3:18 a.m. Japan Standard Time, 8 December in Japan.
ISO 8601 is an international standard covering the worldwide exchange and communication of date and time-related data. It is maintained by the International Organization for Standardization (ISO) and was first published in 1988, with updates in 1991, 2000, 2004, and 2019, and an amendment in 2022. The standard provides a well-defined, unambiguous method of representing calendar dates and times in worldwide communications, especially to avoid misinterpreting numeric dates and times when such data is transferred between countries with different conventions for writing numeric dates and times.
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.
Central European Time (CET) is a standard time of Central, and parts of Western Europe, which is one hour ahead of Coordinated Universal Time (UTC). The time offset from UTC can be written as UTC+01:00. It is used in most parts of Europe and in a few North African countries. CET is also known as Middle European Time and by colloquial names such as Amsterdam Time, Berlin Time, Brussels Time, Budapest Time,Madrid Time, Paris Time, Rome Time,Prague time,Warsaw Time or Romance Standard Time (RST).
Western European Time is a time zone covering parts of western Europe and consists of countries using UTC±00:00. It is one of the three standard time zones in the European Union along with Central European Time and Eastern European Time.
Eastern European Time (EET) is one of the names of 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.
Central European Summer Time, sometimes referred to as Central European Daylight Time (CEDT),is the standard clock time observed during the period of summer daylight-saving in those European countries which observe Central European Time during the other part of the year. It corresponds to UTC+02:00, which makes it the same as Eastern European Time, Central Africa Time, South African Standard Time, Egypt Standard Time and Kaliningrad Time in Russia.
UTC−03:00 is an identifier for a time offset from UTC of −03:00.
UTC+02:00 is an identifier for a time offset from UTC of +02:00. In ISO 8601, the associated time would be written as 2020-11-08T23:41:45+02:00. This time is used in:
UTC+03:00 is an identifier for a time offset from UTC of +03:00. In areas using this time offset, the time is three hours later than the Coordinated Universal Time (UTC). Following the ISO 8601 standard, a time with this offset would be written as, for example, 2019-02-08T23:36:06+03:00.
Nepal Standard Time (NPT) is the time zone for Nepal. With a time offset from Coordinated Universal Time (UTC) of UTC+05:45 all over Nepal, it is one of only three time zones with a 45-minute offset from UTC.
The time in China follows a single standard time offset of UTC+08:00 based on the National Time Service Center of Chinese Academy of Sciences located in Mount Li, Lintong District, Xi'an City, Shaanxi Province, even though the country spans almost five geographical time zones. The official national standard time is called Beijing Time domestically because based on 120th meridian east that Beijing City is located, and China Standard Time (CST) internationally. Daylight saving time has not been observed since 1991. China Standard Time (UTC+8) is consistent across Mainland China, Hong Kong, Macau, Taiwan, as well as equivalent with Philippines, Singapore, Brunei, most of Mongolia, Malaysia, Irkutsk Time (Russia), Western Australia and Central Indonesia.
UTC+04:00 is an identifier for a time offset from UTC of +04:00. In ISO 8601, the associated time would be written as 2019-02-07T23:28:34+04:00. This time is used in:
UTC+00:00 is an identifier for a time offset from UTC of +00:00. This time zone is the basis of 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:
Anywhere on Earth (AoE) is a calendar designation that indicates that a period expires when the date passes everywhere on Earth. It is a practice to help specify easy to understand deadlines such as "March 16, 2004, End of Day, Anywhere on Earth (AoE)" without requiring timezone calculations or Daylight saving time adjustments.
Thailand has adopted ISO 8601 under national standard: TIS 1111:2535 in 1992. However, in practice, there are some variations.
Daylight saving time in the Americas is the arrangement in the Americas by which clocks are advanced by one hour in spring and moved back in autumn, to make the most of seasonal daylight. The practice is widespread in North America, with most of Canada and the United States participating, but much less so in Central and South America.
Daylight saving time (DST), also known as summer time, is the practice of advancing clocks during part of the year, typically by one hour around spring and summer, so that daylight ends at a later time of the day. As of 2024, DST is observed in most of Europe, most of North America and parts of Africa and Asia around the Northern Hemisphere summer, and in parts of South America and Oceania around the Southern Hemisphere summer. It was also formerly observed in other areas.
