Time Zone Abbreviations There are several abbreviations often used when referring to time, such as e.g. 11:00 ET which means 11:00 Eastern Time or New York-time. List of abbreviations Standard UTC define the universal time zone, which all the other time zones are relative to. It observes no daylight saving time (summer time). UTC is sometimes adjusted with "leap seconds" so that the difference between UTC time and the Earth's rotational time does not exceed 0.9 seconds. The offset between UTC and TAI is always an integral number of seconds. The last leap second added to UTC was on December 31th 1998 at 23:59:60 UTC (the last minute of 1998 had one extra second). There will be no leap second in June 2000, but maybe in December 2000, it is not yet decided. UTC Universal Time Coordinated, civil time, the one most often used by "ordinary" people UT Universal Time, based on the Earth's rotation, often used in Astronomy TAI International Atomic Time, based on atomic clocks Other abbreviations European GMT Greenwich Mean Time, as UTC BST British Summer Time, as UTC+1 hour IST Irish Summer Time, as UTC+1 hour WET Western Europe Time, as UTC WEST Western Europe Summer Time, as UTC+1 hour CET Central Europe Time, as UTC+1 CEST Central Europe Summer Time, as UTC+2 EET Eastern Europe Time, as UTC+2 EEST Eastern Europe Summer Time, as UTC+3 MSK Moscow Time, as UTC+3 MSD Moscow Summer Time, as UTC+4 US and Canada AST Atlantic Standard Time, as UTC-4 hours ADT Atlantic Daylight Time, as UTC-3 hours EST Eastern Standard Time, as UTC-5 hours EDT Eastern Daylight Saving Time, as UTC-4 hours ET Eastern Time, either as EST or EDT, depending on place and time of year e.g. New York CST Central Standard Time, as UTC-6 hours CDT Central Daylight Saving Time, as UTC-5 hours CT Central Time, either as CST or CDT, depending on place and time of year e.g. Chicago MST Mountain Standard Time, as UTC-7 hours MDT Mountain Daylight Saving Time, as UTC-6 hours MT Mountain Time, either as MST or MDT, depending on place and time of year e.g. Denver PST Pacific Standard Time, as UTC-8 hours PDT Pacific Daylight Saving Time, as UTC-7 hours PT Pacific Time, either as PST or PDT, depending on place and time of year e.g. Los Angeles HST Hawaiian Standard Time, as UTC-10 hours AKST Alaska Standard Time, as UTC-9 hours AKDT Alaska Standard Daylight Saving Time, as UTC-8 hours Australia WST Western Standard Time, as UTC+8 hours e.g. Perth CST Central Standard Time, as UTC+9.5 hours e.g. Darwin EST Eastern Standard/Summer Time, as UTC+10 hours (+11 hours during summer time) e.g. Canberra Time zone letter abbreviations The basis for this is Z - Zulu time - Zero meridian time - the same as UTC It's a convention to assign letters to time zones, where Z= Zero meridian, and Zulu is the word that represents the letter Z, when it's used in communication. It is sometimes used in the US Military and NATO in conjunction with 24 hour clocks, and is also popular to use in movies to reference time. Other letters/words are used for other time zones than UTC, most based on the right or reverse order of the Alphabet, although 'J' is skipped ('J' refers to current local time of the observer) (there are 25 time zones defined here, but 26 letters in the alphabet), Zulu is an exception to this, in the middle, here from the International Date Line, going west, until the International Date Line is reached again. Letter Word Difference. Y Yankee UTC - 12 hours X Xray UTC - 11 hour W Whiskey UTC - 10 hour V Victor UTC - 9 hour U Uniform UTC - 8 hour T Tango UTC - 7 hour S Sierra UTC - 6 hour R Romeo UTC - 5 hour Q Quebec UTC - 4 hour P Papa UTC - 3 hour O Oscar UTC - 2 hour N November UTC - 1 hour Z Zulu same as UTC A Alpha UTC + 1 hour B Bravo UTC + 2 hours C Charlie UTC + 3 hours D Delta UTC + 4 hours E Echo UTC + 5 hours F Foxtrot UTC + 6 hours G Golf UTC + 7 hours H Hotel UTC + 8 hours I India UTC + 9 hours K Kilo UTC + 10 hours L Lima UTC + 11 hours M Mike UTC + 12 hours International Date Line is between time zones M and Y (24 hours/one day differs) The letter 'J' for 'Juliet' is used to refer to local time of the observer. More will follow later Related links