Standard time
Encyclopedia
Standard time is the result of synchronizing clocks in different geographical locations within a time zone
to the same time rather than using the local meridian
as in local mean time
or solar time
. Historically, this helped in the process of weather forecasting
and train travel. The concept became established in the late 19th century. The time so set has come to be defined in terms of offsets from Universal Time
. Where daylight saving time
is used, the term standard time typically refers to the time without daylight saving time.
The adoption of Standard Time, because of the inseparable correspondence between time
and longitude
, solidified the concepts of halving the globe into an eastern
and western hemisphere
, with one Prime Meridian
(as well its opposite International Dateline) replacing the various Prime Meridians that were in use.
reflecting the important role the railway companies played in bringing it about. The vast majority of Great Britain
's public clocks were being synchronised using GMT by 1855.
, resulting in an inordinate number of local times. This caused convoluted regional and national train
schedules. Cleveland Abbe
advocated for standard time in order to more effectively coordinate international weather observations and resultant weather forecasts
, which were coordinated using local solar time
beginning in 1875. He recommended the concept of four time zones across the contiguous United States
, based upon Greenwich Mean Time
, in 1879. Sandford Fleming
, a Canadian
, proposed Standard Time at a meeting of the Royal Canadian Institute
on February 8, 1879. On October 11, 1883, the heads of the major railroads met in Chicago
at the former Grand Pacific Hotel
to adopt the Standard Time System of four standard time zones for the continental U.S.A.. The new system was adopted by most states almost immediately after railroads did so. At noon on November 18, 1883, the U.S. Naval Observatory changed its telegraphic signals to correspond to the change. The Standard Time Act
of 1918 established standard time in time zones in U.S. law as well as daylight saving time (DST). The daylight savings time law was repealed in 1919 over a presidential veto, but reestablished nationally during World War II.
In 2007 the United States
enacted a federal law formalizing the use of Coordinated Universal Time
as the basis of standard time, and the role of the Secretary of Commerce (effectively, the National Institute of Standards and Technology
) and the Secretary of the Navy
(effectively, the U.S. Naval Observatory
) in interpreting standard time.
Time zone
A time zone is a region on Earth that has a uniform standard time for legal, commercial, and social purposes. In order for the same clock time to always correspond to the same portion of the day as the Earth rotates , different places on the Earth need to have different clock times...
to the same time rather than using the local meridian
Meridian (geography)
A meridian is an imaginary line on the Earth's surface from the North Pole to the South Pole that connects all locations along it with a given longitude. The position of a point along the meridian is given by its latitude. Each meridian is perpendicular to all circles of latitude...
as in local mean time
Local mean time
Local mean time is a form of solar time that corrects the variations of local apparent time, forming a uniform time scale at a specific longitude...
or solar time
Solar time
Solar time is a reckoning of the passage of time based on the Sun's position in the sky. The fundamental unit of solar time is the day. Two types of solar time are apparent solar time and mean solar time .-Introduction:...
. Historically, this helped in the process of weather forecasting
Weather forecasting
Weather forecasting is the application of science and technology to predict the state of the atmosphere for a given location. Human beings have attempted to predict the weather informally for millennia, and formally since the nineteenth century...
and train travel. The concept became established in the late 19th century. The time so set has come to be defined in terms of offsets from Universal Time
Universal Time
Universal Time is a time scale based on the rotation of the Earth. It is a modern continuation of Greenwich Mean Time , i.e., the mean solar time on the Prime Meridian at Greenwich, and GMT is sometimes used loosely as a synonym for UTC...
. Where daylight saving time
Daylight saving time
Daylight saving time —also summer time in several countries including in British English and European official terminology —is the practice of temporarily advancing clocks during the summertime so that afternoons have more daylight and mornings have less...
is used, the term standard time typically refers to the time without daylight saving time.
The adoption of Standard Time, because of the inseparable correspondence between time
Time
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
and longitude
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....
, solidified the concepts of halving the globe into an eastern
Eastern Hemisphere
The Eastern Hemisphere, also Eastern hemisphere or eastern hemisphere, is a geographical term for the half of the Earth that is east of the Prime Meridian and west of 180° longitude. It is also used to refer to Europe, Asia, Africa, and Australasia, vis-à-vis the Western Hemisphere, which includes...
and western hemisphere
Western Hemisphere
The Western Hemisphere or western hemisphere is mainly used as a geographical term for the half of the Earth that lies west of the Prime Meridian and east of the Antimeridian , the other half being called the Eastern Hemisphere.In this sense, the western hemisphere consists of the western portions...
, with one Prime Meridian
Prime Meridian
The Prime Meridian is the meridian at which the longitude is defined to be 0°.The Prime Meridian and its opposite the 180th meridian , which the International Date Line generally follows, form a great circle that divides the Earth into the Eastern and Western Hemispheres.An international...
(as well its opposite International Dateline) replacing the various Prime Meridians that were in use.
Great Britain
A standardized time system was first used by British railways on December 11, 1847, when they switched from local mean time to Greenwich Mean Time (GMT). It was also given the name Railway timeRailway time
Railway time was the name given to the standardised time arrangement first applied by the Great Western Railway in England in November 1840. This was the first recorded occasion when a number of different local times were synchronised and a single standard time applied...
reflecting the important role the railway companies played in bringing it about. The vast majority of Great Britain
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
's public clocks were being synchronised using GMT by 1855.
North America
Prior to 1883, local mean time was used throughout North AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
, resulting in an inordinate number of local times. This caused convoluted regional and national train
Train
A train is a connected series of vehicles for rail transport that move along a track to transport cargo or passengers from one place to another place. The track usually consists of two rails, but might also be a monorail or maglev guideway.Propulsion for the train is provided by a separate...
schedules. Cleveland Abbe
Cleveland Abbe
Cleveland Abbe was an American meteorologist and advocate of time zones. While director of the Cincinnati Observatory in Cincinnati, Ohio, he developed a system of telegraphic weather reports, daily weather maps, and weather forecasts. Congress in 1870 established the U.S. Weather Bureau and...
advocated for standard time in order to more effectively coordinate international weather observations and resultant weather forecasts
Weather forecasting
Weather forecasting is the application of science and technology to predict the state of the atmosphere for a given location. Human beings have attempted to predict the weather informally for millennia, and formally since the nineteenth century...
, which were coordinated using local solar time
Solar time
Solar time is a reckoning of the passage of time based on the Sun's position in the sky. The fundamental unit of solar time is the day. Two types of solar time are apparent solar time and mean solar time .-Introduction:...
beginning in 1875. He recommended the concept of four time zones across the contiguous United States
Contiguous United States
The contiguous United States are the 48 U.S. states on the continent of North America that are south of Canada and north of Mexico, plus the District of Columbia....
, based upon Greenwich Mean Time
Greenwich Mean Time
Greenwich Mean Time is a term originally referring to mean solar time at the Royal Observatory in Greenwich, London. It is arguably the same as Coordinated Universal Time and when this is viewed as a time zone the name Greenwich Mean Time is especially used by bodies connected with the United...
, in 1879. Sandford Fleming
Sandford Fleming
Sir Sandford Fleming, was a Scottish-born Canadian engineer and inventor, proposed worldwide standard time zones, designed Canada's first postage stamp, a huge body of surveying and map making, engineering much of the Intercolonial Railway and the Canadian Pacific Railway, and was a founding...
, a Canadian
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...
, proposed Standard Time at a meeting of the Royal Canadian Institute
Royal Canadian Institute
The Royal Canadian Institute, or RCI, is an organization dedicated to the advancement of science.First formed in 1849 by Sir Sandford Fleming, it was originally conceived of as an organization for engineers and surveyors, but quickly became more general in its scientific interests. Incorporated in...
on February 8, 1879. On October 11, 1883, the heads of the major railroads met in Chicago
Chicago
Chicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...
at the former Grand Pacific Hotel
Grand Pacific Hotel (Chicago)
The Grand Pacific Hotel was one of the first two prominent hotels built in Chicago, Illinois after the Great Chicago Fire. The hotel, designed by William W...
to adopt the Standard Time System of four standard time zones for the continental U.S.A.. The new system was adopted by most states almost immediately after railroads did so. At noon on November 18, 1883, the U.S. Naval Observatory changed its telegraphic signals to correspond to the change. The Standard Time Act
Standard Time Act
The Standard Time Act, , also known as the Calder Act, was the first United States federal law implementing standard time and Daylight saving time in the United States. It authorized the Interstate Commerce Commission to define each time zone....
of 1918 established standard time in time zones in U.S. law as well as daylight saving time (DST). The daylight savings time law was repealed in 1919 over a presidential veto, but reestablished nationally during World War II.
In 2007 the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
enacted a federal law formalizing the use of Coordinated Universal Time
Coordinated Universal Time
Coordinated Universal Time is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time. Computer servers, online services and other entities that rely on having a universally accepted time use UTC for that purpose...
as the basis of standard time, and the role of the Secretary of Commerce (effectively, the National Institute of Standards and Technology
National Institute of Standards and Technology
The National Institute of Standards and Technology , known between 1901 and 1988 as the National Bureau of Standards , is a measurement standards laboratory, otherwise known as a National Metrological Institute , which is a non-regulatory agency of the United States Department of Commerce...
) and the Secretary of the Navy
United States Navy
The United States Navy is the naval warfare service branch of the United States Armed Forces and one of the seven uniformed services of the United States. The U.S. Navy is the largest in the world; its battle fleet tonnage is greater than that of the next 13 largest navies combined. The U.S...
(effectively, the U.S. Naval Observatory
United States Naval Observatory
The United States Naval Observatory is one of the oldest scientific agencies in the United States, with a primary mission to produce Positioning, Navigation, and Timing for the U.S. Navy and the U.S. Department of Defense...
) in interpreting standard time.
See also
- Time zoneTime zoneA time zone is a region on Earth that has a uniform standard time for legal, commercial, and social purposes. In order for the same clock time to always correspond to the same portion of the day as the Earth rotates , different places on the Earth need to have different clock times...
- Universal TimeUniversal TimeUniversal Time is a time scale based on the rotation of the Earth. It is a modern continuation of Greenwich Mean Time , i.e., the mean solar time on the Prime Meridian at Greenwich, and GMT is sometimes used loosely as a synonym for UTC...
- Daylight saving timeDaylight saving timeDaylight saving time —also summer time in several countries including in British English and European official terminology —is the practice of temporarily advancing clocks during the summertime so that afternoons have more daylight and mornings have less...
- International Meridian ConferenceInternational Meridian ConferenceThe International Meridian Conference was a conference held in October 1884 in Washington, D.C., in the United States to determine the Prime Meridian of the world. The conference was held at the request of U.S. President Chester A...
of 1884 - Mecca TimeMecca TimeMecca Time is a time standard that uses the line of longitude that goes through Mecca, Saudi Arabia as its Prime Meridian. Its proposed use as a global standard is based on the claim that the city is the true center of the Earth and thus should become the basis of the world's timezones...