Standard time is the synchronization of clocks within a geographical region to a single time standard, rather than alocal mean time standard. The term is also used to contrast withdaylight saving time, a period of the year when clocks are shifted ahead one hour, supposedly to make better use of daily sunlight from spring to fall. Applied globally in the 20th century, the geographical regions becametime zones. The standard time in each time zone has come to be defined as anoffset from Universal Time. A further offset is applied for part of the year in regions withdaylight saving time. Generally, standard time agrees with the local mean time at some meridian that passes through the region, often near the centre of the region. Historically, standard time was established during the 19th century to aidweather forecasting and train travel.
The adoption of standard time, because of the inseparable correspondence betweenlongitude and time, solidified the concept of halving the globe into theEastern Hemisphere and theWestern Hemisphere, with onePrime Meridian replacing thevarious prime meridians that had previously been used.
During the 19th century, scheduled steamships and trains required time standardisation in the industrialized world.
A standardised time system was first used by British railways on 1 December 1847, when they switched from local mean time, which varied from place to place, toGreenwich Mean Time (GMT). It was also given the namerailway time, reflecting the important role the railway companies played in bringing it about. The vast majority of Great Britain's public clocks were standardised to GMT by 1855.
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Until 1883, each United States railroad chose its own time standards. ThePennsylvania Railroad used the "Allegheny Time" system, an astronomical timekeeping service which had been developed bySamuel Pierpont Langley at theUniversity of Pittsburgh'sAllegheny Observatory (then known as theWestern University of Pennsylvania, located inPittsburgh, Pennsylvania). Instituted in 1869, the Allegheny Observatory's service is believed to have been the first regular and systematic system of time distribution to railroads and cities as well as the origin of the modern standard time system.[1] By 1870 the Allegheny Time service extended over 2,500 miles with 300 telegraph offices receiving time signals.[2]
However, almost all railroads out of New York ran on New York time, and railroads west from Chicago mostly used Chicago time, but between Chicago and Pittsburgh/Buffalo the norm was Columbus time, even on railroads such as the PFtW&C andLS&MS, which did not run through Columbus. TheSanta Fe Railroad usedJefferson City (Missouri) time all the way to its west end atDeming, New Mexico, as did the east–west lines across Texas; Central Pacific and Southern Pacific Railroads used San Francisco time all the way toEl Paso. TheNorthern Pacific Railroad had seven time zones between St. Paul and the 1883 west end of the railroad atWallula Jct; the Union Pacific Railway was at the other extreme, with only two time zones betweenOmaha and Ogden.[3]
In 1870,Charles F. Dowd proposed four time zones based on themeridian throughWashington, DC, for North American railroads.[4] In 1872 he revised his proposal to base it on theGreenwich meridian.Sandford Fleming, a Scottish-born Canadian engineer, proposed worldwide Standard Time at a meeting of theRoyal Canadian Institute on February 8, 1879.[5]Cleveland Abbe advocated standard time to better coordinate international weather observations and resultantweather forecasts, which had been coordinated using localsolar time. In 1879 he recommended four time zones across thecontiguous United States, based uponGreenwich Mean Time.[6] The General Time Convention (renamed theAmerican Railway Association in 1891), an organization of US railroads charged with coordinating schedules and operating standards, became increasingly concerned that if the US government adopted a standard time scheme it would be disadvantageous to its member railroads. William F. Allen, the Convention secretary, argued that North American railroads should adopt a five-zone standard, similar to the one in use today, to avoid government action. On October 11, 1883, the heads of the major railroads met inChicago at theGrand Pacific Hotel[7] and agreed to adopt Allen's proposed system.
The members agreed that on Sunday, November 18, 1883, all United States and Canadian railroads would readjust their clocks and watches to reflect the new five-zone system on a telegraph signal from the Allegheny Observatory in Pittsburgh at exactly noon on the 90th meridian.[8][9][10] Although most railroads adopted the new system as scheduled, some did so early on October 7 and others late on December 2. TheIntercolonial Railway serving the Canadian maritime provinces ofNew Brunswick andNova Scotia just east ofMaine decided not to adopt Intercolonial Time based on the 60th meridian west of Greenwich, instead adopting Eastern Time, so only four time zones were actually adopted by American and Canadian railroads in 1883.[9] Major American observatories, including the Allegheny Observatory, theUnited States Naval Observatory, theHarvard College Observatory, and theYale University Observatory, agreed to provide telegraphic time signals at noon Eastern Time.[9][10]
Standard time was not enacted into US law until the1918 Standard Time Act established standard time in time zones; the law also instituted daylight saving time (DST). The daylight saving time portion of the law was repealed in 1919 over a presidential veto, but was re-established nationally during World War II.[11][12] In 2007 the US enacted a federal law formalising the use ofCoordinated Universal Time as the basis of standard time, and the role of theSecretary of Commerce (effectively, theNational Institute of Standards and Technology) and theSecretary of the Navy (effectively, theUS Naval Observatory) in interpreting standard time.[13]
In 1999, standard time was inducted into theNorth America Railway Hall of Fame in the category "National: Technical Innovations."[14]
TheDominion of Newfoundland, whose capital St. John's falls almost exactly midway between the meridians anchoring theAtlantic Time Zone and theGreenland Time Zone, voted in 1935 to create a half-hour offset time zone known as theNewfoundland Time Zone, at three and a half hours behind Greenwich time.
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In the Netherlands, introduction of the railways made it desirable to create a standard time. On 1 May 1909,Amsterdam Time or Dutch Time was introduced. Before that, time was measured in different cities; in the east of the country, this was a few minutes earlier than in the west. After that, all parts of the country had the same local time—that of the Wester Tower inAmsterdam (Westertoren/4°53'01.95" E). This time was indicated as GMT +0h 19m 32.13s until 17 March 1937, after which it was simplified to GMT+0h20m. This time zone was also known as theLoenen time orGorinchem time, as this was the exact time in bothLoenen andGorinchem. At noon in Amsterdam, it was 11:40 inLondon and 12:40 inBerlin.
The shift to the currentCentral European Time zone took place on 16 May 1940. The German occupiers ordered the clock to be moved an hour and forty minutes forward. This time was kept in summer and winter throughout 1941 and 1942. It was only in November 1942 that a different Winter time was introduced, and the time was adjusted one hour backwards. This lasted for only three years; after the liberation of the Netherlands in 1945, Summer time was abolished for over thirty years, so during those years, standard time was 40 minutes ahead of the original Amsterdam Time. As of 2017, the Netherlands is in line with Central European Time (GMT+1 in the winter, GMT+2 in the summer, which is significantly different from Amsterdam Time).
In September 1868, New Zealand was the first country in the world to establish a nationwide standard time.[15]
Atelegraph cable between New Zealand's two main islands became the instigating factor for the establishment of "New Zealand time". In 1868, the Telegraph Department adopted "Wellington time" as the standard time across all their offices so that opening and closing times could be synchronised. The Post Office, which usually shared the same building, followed suit. However, protests that time was being dictated by one government department, led to a resolution in parliament to establish a standard time for the whole country.
The director of the Geological Survey,James Hector, selected New Zealand time to be at the meridian 172°30′E. This was very close to the country's meanlongitude and exactly 11.5 hours in advance of Greenwich Mean Time. It came into effect on 2 November 1868.
For over fifty years, theColonial Time Service Observatory in Wellington, determined the correct time each morning. At 9 a.m. each day, it was transmitted byMorse code to post offices and railway stations around the country. In 1920, radio time signals began broadcasting, greatly increasing the accuracy of the time nationwide.
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