 | The examples and perspective in this article deal primarily with the United States and do not represent a worldwide view of the subject.(August 2021) |
Various proposals have been made to replace the system of time zones with Coordinated Universal Time (UTC) as a local time.
For most of history, the position of the sun was used for timekeeping. During the 19th century, most towns kept their own local time. The standardization of time zones started in 1884 in the US. [1]
The time-zone map is a hodgepodge — a jigsaw puzzle by Dalí.
Arthur C. Clarke proposed the use of a single time zone in 1976. [2] Attempts to abolish time zones date back half a century [1] and include the Swatch Internet Time. Economics professor Steve Hanke and astrophysics professor Dick Henry at Johns Hopkins University have been proponents of the concept and have integrated it in their Hanke–Henry Permanent Calendar. [3] [4] [5] [6]
UTC as a universal time zone is already used by airline operators around the world [7] and other international settings where time coordination is especially critical. This includes military operations, the US National Oceanic and Atmospheric Administration and the International Space Station. [8] Within the United States, some have cited effective international use of UTC in certain industries as evidence that a permanent national time zone would work within the United States, a change the Secretary of Transportation would have the authority to make. [8]
For example, at 08:00 (8 AM), with UTC±0 as a worldwide standard, the sky in the Eastern United States would look how it normally does at 03:00 (3 AM), and in China would look how it does at 16:00 (4 PM). However, in the United Kingdom, the sky would look the exact same as it normally does at 08:00 (8 AM).
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.
Japan Standard Time, or Japan Central Standard Time, is the standard time zone in Japan, 9 hours ahead of UTC (UTC+09:00). Japan does not observe daylight saving time, though its introduction has been debated on several occasions. During World War II, the time zone was often referred to as Tokyo Standard Time.
The North American Central Time Zone (CT) is a time zone in parts of Canada, the United States, Mexico, Central America, and some Caribbean islands.
The Eastern Time Zone (ET) is a time zone encompassing part or all of 23 states in the eastern part of the United States, parts of eastern Canada, and the state of Quintana Roo in Mexico.
The Pacific Time Zone (PT) is a time zone encompassing parts of western Canada, the western United States, and western Mexico. Places in this zone observe standard time by subtracting eight hours from Coordinated Universal Time (UTC−08:00). During daylight saving time, a time offset of UTC−07:00 is used.
The Alaska Time Zone observes standard time by subtracting nine hours from Coordinated Universal Time (UTC−09:00). During daylight saving time its time offset is eight hours (UTC−08:00). The clock time in this zone is based on mean solar time at the 135th meridian west of the Greenwich Observatory.
In the United States, time is divided into nine standard time zones covering the states, territories and other US possessions, with most of the country observing daylight saving time (DST) for approximately the spring, summer, and fall months. The time zone boundaries and DST observance are regulated by the Department of Transportation, but no single map of those existed until the agency announced intentions to make one in September 2022. Official and highly precise timekeeping services (clocks) are provided by two federal agencies: the National Institute of Standards and Technology (NIST) ; and the United States Naval Observatory (USNO). The clocks run by these services are kept synchronized with each other as well as with those of other international timekeeping organizations.
Summer time in Europe is the variation of standard clock time that is applied in most European countries in the period between spring and autumn, during which clocks are advanced by one hour from the time observed in the rest of the year, with a view to making the most efficient use of seasonal daylight. It corresponds to the notion and practice of daylight saving time (DST) to be found in some other parts of the world.
Moscow Time is the time zone for the city of Moscow, Russia, and most of western Russia, including Saint Petersburg. It is the second-westernmost of the eleven time zones of Russia. It has been set to UTC+03:00 without DST since 26 October 2014; before that date it had been set to UTC+04:00 year-round on 27 March 2011.
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 ahead of 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.
Australia uses three main time zones: Australian Eastern Standard Time, Australian Central Standard Time and Australian Western Standard Time.
There are 11 time zones in Russia, which currently observe times ranging from UTC+02:00 to UTC+12:00. Daylight saving time (DST) has not been used in Russia since 26 October 2014. From 27 March 2011 to 26 October 2014, permanent DST was used.
Time in Brazil is calculated using standard time, and the country is divided into four standard time zones: UTC−02:00, UTC−03:00, UTC−04:00 and UTC−05:00.
Iran Standard Time (IRST) or Iran Time (IT) is the time zone used in Iran. Iran uses a UTC offset UTC+03:30. IRST is defined by the 52.5 degrees east meridian, the same meridian which defines the Iranian calendar and is the official meridian of Iran.
Most of the United States observes daylight saving time (DST), the practice of setting the clock forward by one hour when there is longer daylight during the day, so that evenings have more daylight and mornings have less. Exceptions include Arizona, Hawaii, and the territories of American Samoa, Guam, the Northern Mariana Islands, Puerto Rico, and the United States Virgin Islands. The Uniform Time Act of 1966 established a uniform set of rules for states opting to observe daylight saving time.
As of 2022, daylight saving time is used in the following Asian countries:
The Hanke–Henry Permanent Calendar (HHPC) is a proposal for calendar reform. It is one of many examples of leap week calendars, calendars that maintain synchronization with the solar year by intercalating entire weeks rather than single days. It is a modification of a previous proposal, Common-Civil-Calendar-and-Time (CCC&T). With the Hanke–Henry Permanent Calendar, every calendar date always falls on the same day of the week. A major feature of the calendar system is the abolition of time zones.
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.
The 2018 Players' Championship was held from April 10 to 15, 2018 at the Mattamy Athletic Centre in Toronto, Ontario. It was the seventh men's and sixth women's Grand Slam event of the 2017–18 World Curling Tour.
Finland uses Eastern European Time (EET) during the winter as standard time and Eastern European Summer Time (EEST) during the summer as daylight saving time. EET is two hours ahead of coordinated universal time (UTC+02:00) and EEST is three hours ahead of coordinated universal time (UTC+03:00). Finland adopted EET on 30 April 1921, and has observed daylight saving time in its current alignment since 1981 by advancing the clock forward one hour at 03:00 EET on the last Sunday in March and back at 04:00 EET on the last Sunday in October, doing so an hour earlier for the first two years.
| International standards |
|   |
|---|---|---|
| Obsolete standards | ||
| Time in physics | ||
| Horology | ||
| Calendar | ||
| Archaeology and geology | ||
| Astronomical chronology | ||
| Other units of time | ||
| Related topics | ||