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. The time so set has come to be defined in terms of offsets from Universal Time. (See more about standard time.)

Where daylight saving time is used the term standard time typically refers to the time without daylight saving time. Contents 1 History of standard time 1.1 Great Britain 1.2 North America 2 See also 3 References 4 Further reading History of standard time 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 time 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. North America

Prior to 1883 local mean time was used throughout North America resulting in an inordinate number of local times. This caused convoluted regional and national train schedules. 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 Hotel1 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.2 The Standard Time Act of 1918 established standard time in time zones in U.S. law as well as daylight saving time (DST). The law was repealed in 1919 over a presidential veto but reestablished nationally during World War II.34

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.5 See also Solar time Time zone Universal Time Daylight saving time References Picture of plaque at the site http://www.usno.navy.mil/USNO/astronomical-applications/astronomical-information-center/us-zones http://www.nationalatlas.gov/mld/timeznp.html Source: CRS Report to Congress 1 s:Congressional Research Service Report RS22284 Daylight Saving Time 21st Century Competitiveness Act of 2007 Section 3013. H.R. 2272: 110th CONGRESS House Bills January 4 2007. Further reading Ian R. Bartky (January 1989). "The adoption of standard time". Technology and Culture 30 (1): 2556. doi:10.2307/3105430. JSTOR 3105430.  Eviatar Zerubavel (July 1982). "The standardization of time: a sociohistorical perspective". The American Journal of Sociology 88 (1): 123. doi:10.1086/227631. JSTOR 2779401.  "World Time Scales". National Institute of Standards and Technology Physics Laboratory. 2002. Archived from the original on July 29 1997. http://web.archive.org/web/19970729054246/http://physics.nist.gov/GenInt/Time/world.html. Retrieved August 26 1997.  This standards- or measurement-related article is a stub. You can help Wikipedia by expanding it.v d e