Due to the spinning of planet Earth, its orbit around the sun and the alternation of night and day there is always a difference in timing between countries based on there geographical location and their longitudinal position.
When telling the time internationally indicating the time difference between countries we use the Greenwich Mean Time with the abbreviation GMT. Greenwich is a district in London the capital of the UK and its timing is used as a standard to compare the international timing differences.
Cities located on the map east of Greenwich, London based on the longitudinal location will have an advancement in time compared to Greenwich so these cities timing will have the timing GMT + as the sun rise in these cities earlier than Greenwich. On the other hand cities located based on longitudinal position west of Greenwich, London will have delay in timing compared to Greenwich because the sun rises in London earlier compared to these cities that will have a timing GMT -.
The timing system used in aviation is the same and it use the abbreviation UTC that stands for Universal Time Coordinated. UTC is the same as GMT and it is used since 1960 so the timing in London will be UTC + or – 0. The following table show the difference in timing between major cities of the world.
|Difference in timing based on GMT||Cities that follow this timing|
|GMT-11||Midway Islands, Samoa|
|GMT-8||Pacific Time (US and Canada), Tijuana|
|GMT-7||Mountain Time (US and Canada)|
|GMT-6||Central Time (US and Canada), Mexico City, Saskatchewan|
|GMT-5||Eastern Time (US and Canada), Bogota, Lima|
|GMT-4||The timing of the Atlantic (Canada), Caracas, La Paz|
|GMT-3||Brasilia, Buenos Aires, Georgetown|
|GMT-1||Azores, Cape Verde Islands|
|GMT + 0||Greenwich Mean Time … Dublin, Edinburgh, London, Lisbon, Casablanca|
|GMT + 1||Berlin, Stockholm, Rome, Vienna, Paris, Madrid, Prague, Warsaw|
|GMT + 2||Athens, Helsinki, Istanbul, Cairo, Eastern Europe, Pretoria, Israel|
|GMT + 3||Baghdad, Kuwait, Nairobi, Riyadh, Moscow, St. Petersburg|
|GMT + 3.5||Tehran|
|GMT + 4||Abu Dhabi, Muscat, Tbilisi, Kazan, Volgograd|
|GMT + 4.5||Kabul|
|GMT + 5||Islamabad, Karachi, Ekaterinburg, Tashkent|
|GMT + 5.5||Bombay, Calcutta, Madras, New Delhi, Colombo|
|GMT + 6||Almaty, Dhaka|
|GMT + 7||Bangkok, Jakarta|
|GMT + 8||Beijing, Hong Kong, Perth, Singapore, Taipei|
|GMT + 9||Tokyo, Osaka, Sapporo, Seoul, Yakutsk|
|GMT + 9.5||Adelaide, Darwin|
|GMT + 10||Brisbane, Canberra, Melbourne, Sydney, Guam, Vladivostok|
|GMT + 11||Magadan, Solomon Islands, New Caledonia|
|GMT + 12||Wellington, Auckland, Fiji, Marshall Islands and Kamchatka|