Standard time is the synchronisation of clocks within a geographical region to a single time standard, rather than a local mean time standard. 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 aid weather forecasting and train travel. Applied globally in the 20th century, the geographical regions became time zones. The standard time in each time zone has come to be defined as an offset from Universal Time. A further offset is applied for part of the year in regions with daylight saving time.

The adoption of standard time, because of the inseparable correspondence between time and longitude, solidified the concept of halving the globe into an eastern and western hemisphere, with one prime meridian replacing the various prime meridians that had previously been used.



Sir Sandford Fleming (January 7, 1827 – July 22, 1915) was a Scottish Canadian engineer and inventor. Born and raised in Scotland, he emigrated to colonial Canada at the age of 18. He promoted worldwide standard time zones, a prime meridian, and use of the 24-hour clock as key elements to communicating the accurate time, all of which influenced the creation of Coordinated Universal Time. He designed Canada's first postage stamp, produced a great deal of work in the fields of land surveying and map making, engineered much of the Intercolonial Railway and the first several hundred kilometers of the Canadian Pacific Railway, and was a founding member of the Royal Society of Canada and founder of the Canadian Institute (a science organization in Toronto).