In the 19th century, as transportation and telecommunications improved, it became increasingly inconvenient for each location to observe its own solar time. Main article: Railway time Plaque commemorating the Railway General Time Convention of 1883 in North America The control panel of the Time Zone Clock in front of Coventry Transport Museum
DST is usually used for about half of the year, typically by adding one hour to local time during spring and summer. The UTC offsets range from UTC−12:00 to UTC+14:00, and are usually a whole number of hours, but a few zones are offset by an additional 30 or 45 minutes (such as in India, South Australia and Nepal).Īreas of extreme latitude are more likely to use DST. Some time zones switch between offsets throughout the year due to daylight saving time (DST). Time zones are defined as one or two offsets from Coordinated Universal Time (UTC), and (if two offsets are used) the days when the offset changes. Time zones tend to follow the boundaries between countries and their subdivisions instead of strictly following longitude, because it is convenient for areas in frequent communication to keep the same time.
For other uses, see Time zone (disambiguation).Ī time zone is an area which observes a uniform standard time for legal, commercial and social purposes. For more time zone lists, see Lists of time zones. For a list of time zones by country, see List of time zones by country. In military GMT is known as Zulu time.Greenwich Mean Time was the same as Universal Time (UT), until the introduction of UTC in 1972 a standard astronomical concept used in many technical fields.This article is about time zones in general. It is now often used to refer to Coordinated Universal Time (UTC) when this is viewed as a time zone, and in casual use for the most parts it is the same. Greenwich Mean Time (GMT) originally referred to the mean solar time at the Royal Observatory in Greenwich, London. Other major cities in the area are Abidjan, Dakar, Grand Dakar, Accra Principal Cities: The largest city in the GMT timezone is London from United Kingdom with population about 7.557 million people. Offset: GMT is 0 hours ahead Greenwich Mean Time (GMT) and is used in EuropeĬountries: It is used in following countries: Burkina Faso, Côte d'Ivoire, Britain (UK), Guernsey, Ghana, Greenland, Gambia, Guinea, Guinea-Bissau, Ireland, Isle of Man, Iceland, Jersey, Liberia, Mali, Mauritania, St Helena, Sierra Leone, Senegal, Sao Tome & Principe, Togo Offset UTC +5:30 hoursġ1:00 pm 23:00 Universal Time Coordinated (UTC). Offset UTC 0:00 hoursĤ:30 am 04:30 India Standard Time (IST). Greenwich Mean Time is 5 hours and 30 minutes behind India Standard Time and 0 hours ahead of Universal Time Coordinated and 0 hours ahead of Greenwich Mean Timeġ1:00 pm 23:00 in GMT is 4:30 am 04:30 in IST and is 11:00 pm 23:00 in UTC and is 11:00 pm 23:00 in GMTīest time for a conference call or a meeting is between 8am-12:30pm in GMT which corresponds to 1:30pm-6pm in ISTīest time for a conference call or a meeting is between 8am-6pm in GMT which corresponds to 8am-6pm in UTCīest time for a conference call or a meeting is between 8am-5pm in GMT which corresponds to 9am-6pm in BSTġ1:00 pm 23:00 Greenwich Mean Time (GMT).