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Question: What Are Time Zones? And What Do The Abbreviations Mean?

• TIME ZONE ABBREVIATIONS
• LIST OF ABBREVIATIONS
• MAP
• OTHER ABBREVIATIONS
• WHAT DOES THIS ALL MEAN?
• TIME ZONE LETTER ABBREVIATIONS

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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 - 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. The most accurate time base.

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 ITC 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 31st 1998 at 23:59:60 UTC [the last minute of 1998 had one extra second]. The next leap second is not yet decided, but there will be no leap second in 1999.

Following map courtesy of the U.S. Naval Observatory

Following Map courtesy of "International Time Zones" web page

OTHER ABBREVIATIONS:

European

• GMT - Greenwich Mean Time = UTC

• BST - British Summer Time = UTC+1

• IST - Irish Summer time = UTC+1

• WET - Western Europe Time = UTC

• WEST - Western Europe Summer Time = UTC+1

• CET - Central Europe Time = UTC+1

• CEST - Central Europe Summer Time = UTC+2

• EET - Eastern Europe Time = UTC+2

• EEST - Eastern Europe Summer time = UTC+3

• MSK - Moscow Time = UTC+3

• MSD - Moscow Summer Time = UTC+4

US and Canada

• AST - Atlantic Standard time = UTC-4

• ADT - Atlantic Daylight Time = UTC-3

• EST - Eastern Standard Time = UTC-5

• EDT - Eastern Daylight Time = UTC-4

• ET - Eastern Time [either as EST or EDT]

• CST - Central Standard time = UTC-6

• CDT - Central Daylight time = UTC-5

• CT - Central Time [either as CST or CDT]

• MST - Mountain Standard Time = UTC-7

• MDT - Mountain Daylight time = UTC-6

• MT - Mountain Time [either as MST or MDT]

• PST - Pacific Standard Time = UTC-8

• PDT - Pacific Daylight Time = UTC-7

• PT - Pacific Time [either PST or PDT]

• HST - Hawaiian Standard Time = UTC-10

• AKST - Alaska Standard Time = UTC-9

• AKDT - Alaska Daylight Time = UTC-8

AUSTRALIA

• WST - Western Standard Time = UTC+8 [e.g. Perth]

• CST - Central Standard Time = UTC+9.5 [e.g. Darwin]

• EST - Eastern Standard/Summer Time = UTC+10 {+11 during summer time: e.g. Canberra]

WHAT DOES THIS ALL MEAN?

Let's say you live in Tacoma, WA [how convenient :}] and you want to know what time it would be in Moscow, Russia.

Well… Tacoma is PST right now [UTC-7] and Moscow is MSK [UTC+3]. UTC = 0 or 0000/2400. UTC-7 is 7 hours earlier, making it 7 hours before midnight - 1700 hours/5:00 PM. Moscow is 3 hours after 0000/2400 making it 0300 there. 7+3=10. There's a 10 hour difference between the two cities. It's also the next day in Moscow as UTC=0 is the 'International dateline' and it changes days there. So it may be Friday night in Tacoma, but it's Saturday morning in Moscow.

For more information on time zone conversions, go to: "The Time Zone Convertor" or "World Time Zone" .

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.