Editing Universal Time (section)

===Adoption in various countries===
The table shows the dates of adoption of time zones based on the Greenwich meridian, including half-hour zones.
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{|
! width=60 align=left | Year 
!  align=left | Countries<ref>{{harvnb|Howse|1980|pp=154–5}}. Names have not been updated.</ref>
|-
| 1847 || Great Britain<ref name=londontime/>
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| 1880 || Ireland (entire island)
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| 1883 || Canada, United States{{efn|legal in 1918 ([[Standard Time Act]])}}
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| 1884 || Serbia 
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| 1886 || New Zealand<ref>{{Cite news |last=Stafford |first=E. W. |date=30 October 1868 |title=The New Zealand Gazette |url=https://library.victoria.ac.nz/databases/nzgazettearchive/pubs/gazettes/1868/1868%20ISSUE%20061.pdf }}</ref>
|-
| 1888 || Japan 
|-
| 1892 || Belgium, the Netherlands,{{efn|Legal time reverted to Amsterdam time 1909; to Central European Time 1940.}} S. Africa{{efn|except Natal}} 
|-
| 1893 || Italy, Germany, Austria-Hungary (railways) 
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| 1894 || Bulgaria, Denmark, Norway, Switzerland, Romania, Turkey (railways) 
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| 1895 || Australia, Natal 
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| 1896 || Formosa (Taiwan)
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| 1899 || Puerto Rico, Philippines 
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| 1900 || Sweden, Egypt, Alaska 
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| 1901 || Spain 
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| 1902 || Mozambique, Rhodesia 
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| 1903 || Ts'intao, Tientsin 
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| 1904 || China Coast, Korea, Manchuria, N. Borneo 
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| 1905 || Chile 
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| 1906 || India (except Calcutta), Ceylon (Sri Lanka), Seychelles 
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| 1907 || Mauritius, Chagos 
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| 1908 || Faroe Is., Iceland 
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| 1911 || France, Algeria, Tunis, many French overseas possessions, British West Indies 
|-
| 1912 || Portugal and overseas possessions, other French possessions, Samoa, Hawaii, Midway and Guam, Timor, Bismarck Arch., Jamaica, Bahamas Is. 
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| 1913 || British Honduras, Dahomey 
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| 1914 || Albania, Brazil, Colombia 
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| 1916 || Greece, Poland, Turkey 
|}
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{|
! width=60 align=left | Year 
!  align=left | Countries
|-
| 1917 || Iraq, Palestine 
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| 1918 || Guatemala, Panama, Gambia, Gold Coast 
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| 1919 || Latvia, Nigeria 
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| 1920 || Argentina, Uruguay, Burma, Siam 
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| 1921 || Finland, Estonia, Costa Rica 
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| 1922 || Mexico 
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| 1924 || Java, USSR 
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| 1925 || Cuba 
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| 1928 || China Inland 
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| 1930 || Bermuda 
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| 1931 || Paraguay 
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| 1932 || Barbados, Bolivia, Dutch East Indies 
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| 1934 || Nicaragua, E. Niger 
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| By 1936 || Labrador, Norfolk I. 
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| By 1937 || Cayman Is., Curaçao, Ecuador, Newfoundland 
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| By 1939 || Fernando Po, Persia 
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| By 1940 || Lord Howe I. 
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| 1940 || The Netherlands 
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| By 1948 || Aden, Ascension I., Bahrain, British Somaliland, Calcutta, Dutch Guiana, Kenya, Federated Malay States, Oman, Straits Settlements, St. Helena, Uganda, Zanzibar 
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| By 1953 || Rarotonga, South Georgia 
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| By 1954 || Cook Is. 
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| By 1959 || Maldive I. Republic 
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| By 1961 || Friendly Is., Tonga Is. 
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| By 1962 || Saudi Arabia 
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| By 1964 || Niue Is. 
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| 1972 || Liberia 
|}
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Apart from [[Nepal Standard Time]] (UTC+05:45), the [[Chatham Standard Time Zone]] (UTC+12:45) used in New Zealand's [[Chatham Islands]]{{sfn|HM Nautical Almanac Office|2015}} and the officially unsanctioned [[Eucla, Western Australia#Time zone|Central Western Time Zone]] (UTC+8:45) used in [[Eucla, Western Australia]] and surrounding areas, all time zones in use are defined by an offset from UTC that is a multiple of half an hour, and in most cases a multiple of an hour.{{citation needed|date=February 2024}}