|-01:00||Cape Verde Time|
|±00:00||Greenwich Mean Time|
|+01:00||West Africa Time|
|+03:00||East Africa Time|
South African Standard Time (SAST) is the time zone used by all of South Africa as well as Eswatini and Lesotho. The zone is two hours ahead of UTC (UTC+02:00) and is the same as Central Africa Time. Daylight saving time is not observed in either time zone. Solar noon in this time zone occurs at 30° E in SAST, effectively making Pietermaritzburg at the correct solar noon point, with Johannesburg and Pretoria slightly west at 28° E and Durban slightly east at 31° E. Thus, most of South Africa's population experience true solar noon at approximately 12:00 daily.
The western Northern Cape and Western Cape differ, however. Everywhere on land west of 22°30′ E effectively experiences year-round daylight saving time because of its location in true UTC+01:00 but still being in South African Standard Time. Sunrise and sunset are thus relatively late in Cape Town, compared to the rest of the country.
To illustrate, daylight hours for South Africa's western and eastern-most major cities:
|1 January||1 July|
The South African National Time Standard, or 'SA Time' Master Clock, is maintained at the Time and Frequency Laboratory of the National Metrology Institute of South Africa (NMISA) at Pretoria and is distributed publicly by an NTP Internet Time service.
Before 8 February 1892, there was no uniformity of time in South Africa and local mean time was in use at the various towns. In 1892, a railway conference was held in Bloemfontein and discussed difficulty of working a railway system, in the absence of a uniform time system. The governments of the Orange Free State, Transvaal and the Cape Colony officially adopted a uniform standard time of UTC+01:30 which was defined as mean time 22.5° east of Greenwich.On 1 March 1903 GMT+02:00 was adopted, which became the current UTC+02:00 when UTC replaced GMT for most purposes.
Prior to 1 March 1903, the Colony of Natal was already using a uniform time supplied by the Natal Observatory. The observatory's local mean time was (UTC+01:52).
South Africa observed a daylight saving time of GMT+03:00 (UTC+03:00) between 20 September 1942 to 21 March 1943 and 19 September 1943 to 19 March 1944.
South African Standard Time is defined as "Coordinated Universal Time plus two hours" (UTC+02:00) as defined in South African National Government Gazette No. 40125 of 8 July 2016.
A time zone is a region of the globe that observes a uniform standard time for legal, commercial, and social purposes. Time zones tend to follow the boundaries of countries and their subdivisions instead of longitude, because it is convenient for areas in close commercial or other communication to keep the same time.
Japan Standard Time is the standard time zone in Japan, 9 hours ahead of UTC. There is no daylight saving time, though its introduction has been debated several times. During World War II, it was often called Tokyo Standard Time.
The Alaska Time Zone observes standard time by subtracting nine hours from Coordinated Universal Time (UTC−09:00). During daylight saving time its time offset is eight hours (UTC−08:00). The clock time in this zone is based on mean solar time at the 135th meridian west of the Greenwich Observatory.
Central European Time (CET), used in most parts of Europe and a few North African countries, is a standard time which is 1 hour ahead of Coordinated Universal Time (UTC). The time offset from UTC can be written as UTC+01:00. The same standard time, UTC+01:00, is also known as Middle European Time and under other names like Berlin Time, Warsaw Time and Romance Standard Time (RST), Paris Time or Rome Time.
Time in the United States, by law, is divided into nine standard time zones covering the states, territories and other US possessions, with most of the United States observing daylight saving time (DST) for approximately the spring, summer, and fall months. The time zone boundaries and DST observance are regulated by the Department of Transportation. Official and highly precise timekeeping services (clocks) are provided by two federal agencies: the National Institute of Standards and Technology (NIST) ; and the United States Naval Observatory (USNO). The clocks run by these services are kept synchronized with each other as well as with those of other international timekeeping organizations.
Central European Summer Time (CEST), sometime referred also as Central European Daylight Time (CEDT), is the standard clock time observed during the period of summer daylight-saving in those European countries which observe Central European Time (UTC+01:00) during the other part of the year. It corresponds to UTC+02:00, which makes it the same as Central Africa Time, South African Standard Time and Kaliningrad Time in Russia.
Time in New Zealand is divided by law into two standard time zones. The main islands use New Zealand Standard Time (NZST), 12 hours in advance of Coordinated Universal Time (UTC) / military M (Mike), while the outlying Chatham Islands use Chatham Standard Time (CHAST), 12 hours 45 minutes in advance of UTC / military M^ (Mike-Three).
In modern usage, civil time refers to statutory time scales designated by civilian authorities, or to local time indicated by clocks. Modern civil time is generally standard time in a time zone at a fixed offset from Coordinated Universal Time (UTC) or from Greenwich Mean Time (GMT), possibly adjusted by daylight saving time during part of the year. UTC is calculated by reference to atomic clocks, and was adopted in 1972. Older systems use telescope observations.
Israel Standard Time (IST) is the standard time zone in Israel. It is two hours ahead of UTC (UTC+02:00).
Australia uses three main time zones: Australian Western Standard Time, Australian Central Standard Time, and Australian Eastern Standard Time. Time is regulated by the individual state governments, some of which observe daylight saving time (DST). Australia's external territories observe different time zones.
The time in China follows a single standard time offset of UTC+08:00, despite China spanning five geographical time zones. The official national standard time is called Beijing Time domestically and China Standard Time (CST) internationally. Daylight saving time has not been observed since 1991.
There are eleven time zones in Russia, which currently observe times ranging from UTC+02:00 to UTC+12:00. Daylight saving time is not used in Russia.
The Indonesian archipelago geographically stretches across four time zones from UTC+06:00 in Aceh to UTC+09:00 in Western New Guinea. However, the Indonesian government only recognizes three time zones in its territory:
The tz database is a collaborative compilation of information about the world's time zones, primarily intended for use with computer programs and operating systems. Paul Eggert is its current editor and maintainer, with the organizational backing of ICANN. The tz database is also known as tzdata, the zoneinfo database or IANA time zone database, and occasionally as the Olson database, referring to the founding contributor, Arthur David Olson.
Uzbekistan time is the standard time in Uzbekistan; it is 5 hours ahead of UTC, UTC+05:00. The standard time uses no daylight saving time, though there has been constant debate whether to adopt it in order to increase leisure time.
Europe spans seven primary time zones, excluding summer time offsets. Most European countries use summer time and harmonise their summer time adjustments; see Summer time in Europe for details.
Metropolitan France uses Central European Time and Central European Summer Time. Daylight saving time is observed in Metropolitan France from the last Sunday in March to the last Sunday in October. With its overseas territories, France uses 12 different time zones, more than any other country in the world.
Portugal has two time zones and observes daylight saving time. Continental Portugal and Madeira use UTC+00:00, while the Azores use UTC–01:00. Daylight saving time is observed nationwide from the last Sunday in March to the last Sunday in October, so that every year, continental Portugal and Madeira temporarily use UTC+01:00, and the Azores temporarily use UTC+00:00.
Spain has two time zones and observes daylight saving time. Spain mainly uses Central European Time (GMT+01:00) and Central European Summer Time (GMT+02:00) in Peninsular Spain, the Balearic Islands, Ceuta, Melilla and plazas de soberanía. In the Canary Islands, the time zone is Western European Time (GMT±00:00) and Western European Summer Time (GMT+01:00). Daylight saving time is observed from the last Sunday in March to the last Sunday in October throughout Spain.
Denmark, including the dependencies Faroe Islands and Greenland, uses six different time zones.