By convention, the world's weather communities use a twenty four hour clock, similar to 'military' time based on the 0° longitude meridian, also known as the Greenwich meridian. Prior to 1972, this time was called Greenwich Mean Time (GMT) but is now referred to as Coordinated Universal Time or Universal Time Coordinated (UTC). - latin ante meridiem, meaning before midday, PM or P.M. latin post meridiem, meaning after midday.Letter 'Z' in military time indicates ZULU Time Zone which is equivalent to UTC.-->
This article provides information about date and time fields, and time zones.
Date and time fields
There are three types of date and time fields that correspond to different data types in the database:
- Combined date/time fields – These fields are the preferred method of entering date and time data. The utcdatetime data type stores time and date data in a single field in Coordinated Universal Time (UTC). UTC is the primary time standard by which the world regulates clocks and time. It is, within about 1 second, mean solar time at 0° longitude; it does not observe daylight saving time. Time zones around the world are expressed using positive or negative offsets from UTC. For most purposes, UTC is considered interchangeable with Greenwich Mean Time (GMT). The current version of UTC is defined by International Telecommunications Union Recommendation (ITU-R TF.460-6).
- Date fields – These fields are used to enter dates only. The date data type stores a day, month, and year. However, these values are not stored in UTC and cannot be associated with a time zone.
- Time fields – These fields are used to display the number of seconds that have elapsed since midnight on the current date. The timeofDay data type stores an integer value. Time values are not stored in UTC.
To express UTC times in the local time, you must provide a time zone. The time zone controls the offset from UTC that is the equivalent of the local time. For example, the offset for Moscow is UTC+3. Your preferred time zone is first set according to the Windows locale of your computer, although it might have been changed by an administrator. Your preferred time zone is used only when displaying combined dates and times. To set the preferred time zone for a user, go to Users page. The page will show the list of users of the system. Select the user that you want to set the preferred time zone for, and click User options. On the Language and region tab, select the preferred time zone.
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Time zone abbreviations can be confusing, especially if you aren’t already familiar with the various time zones they represent. If you’re wondering about the abbreviation for Eastern Standard Time (EST) or need to know what UTC means, this handy guide will help.
UTC and GMT: The Prime Meridian
UTC stands for Coordinated Universal Time. This is the world’s standard for regulating clocks and referring to other time zones. Also known as Greenwich Mean Time or GMT, it represents 0° in longitude or the Prime Meridian. The following cities are on or near the Prime Meridian and use UTC or GMT for their time zones:
- London, United Kingdom
- Accra, Ghana
- Valencia, Spain
- Bordeaux, France
Every other time zone represents an adjustment from UTC or GMT in terms of hours before or after it using minus or plus symbols, respectively.
Common World Time Zone Abbreviations
The following list includes some of the most common time zone abbreviations used around the world. Since some countries have their own abbreviations and names for time zones, you’ll find that there’s some overlap between zones.
AEST - Australia Eastern Standard Time
AEST stands for Australia Eastern Standard Time and is UTC +10:00. It’s in use in the eastern portion of Australia. Cities in this time zone include Brisbane and Sydney.
ACST - Australia Central Standard Time
ACST is the abbreviation for Australia Central Standard Time. ACST is UTC +09:30. This time zone represents the central portion of Australia, including the cities of Adelaide and Darwin.
AFT - Afghanistan Time
The country of Afghanistan uses the time zone of Afghanistan Time, which has the abbreviation AFT. This is UTC +04:30.
AKST - Alaska Standard Time
The abbreviation AKST stands for Alaska Standard Time. This time zone is in use in the state of Alaska and is UTC -09:00. During daylight savings time, it changes to AKDT for Alaska Daylight Time.
AST - Atlantic Standard Time
Atlantic Standard Time, abbreviated AST, is a time zone used by several countries. AST is UTC -04:00. During daylight savings time, this time zone is ADT or Atlantic Daylight Time. A few of the places using AST include the following:
- Antigua and Barbuda
- US Virgin Islands
AWST - Australia Western Standard Time
AWST stands for Australia Western Standard Time and is UTC +09:00. AWST is in use in the western portion of Australia, like in the city of Perth.
CAT - Central Africa Time
Central Africa Time is abbreviated as CAT. This time zone is UTC +02:00 and is in use in the following countries:
CET - Central European Time
Central European Time, abbreviated as CET, is used in a number of countries in Europe. It is UTC +01:00. In countries that observe daylight savings, the time zone changes to CEST for Central European Summer Time or CEDT for Central European Daylight Time. A few of the places using CET include the following:
CST - Central Standard Time
In use in the center portion of the United States and Canada, Central Standard Time is abbreviated CST. It is UTC -06:00. During daylight savings time, it changes to CDT or Central Daylight Time. This covers cities like Houston, Mexico City and Winnipeg.
EAT - East Africa Time
In the Eastern portion of Africa, several countries use EAT to abbreviate East Africa Time. EAT is UTC +03:00. It’s in use in the following places:
EET - Eastern European Time
EET is an abbreviation for Easter European Time. EET is UTC +02:00. In countries observing daylight savings time, it changes to EEDT for Eastern European Daylight Time or EEST for Eastern European Summer Time. Countries using EET include the following:
EST - Eastern Standard Time
Is Utc A Time Zone
Much of eastern North America uses EST to abbreviate Eastern Standard Time. This time zone is UTC -05:00. During daylight savings time, it changes to EDT for Eastern Daylight Time. Notable cities include New York, Toronto and Atlanta, as well as Nassau, Lima and Panama City.
MSK - Moscow Standard Time
How To Read Utc Time
MSK is the abbreviation for Moscow Standard Time. MSK is UTC +03:00. In summer, this becomes MSD or Moscow Summer Time. This time zone is in use in the following countries:
- Parts of Russia
- Parts of Ukraine
MST - Mountain Standard Time
Covering the central and some of the western portions of North America, Mountain Standard Time is abbreviated as MST. It is UTC -07:00. During daylight savings time, this becomes, MDT or Mountain Daylight Time. Cities here include Denver, Phoenix and Calgary.
PST - Pacific Standard Time
The western portion of North America is in PST or Pacific Standard Time. PST is UTC -08:00. It becomes PDT or Pacific Daylight Time during daylight savings time. Cities that observe PST include Vancouver, Los Angeles and Las Vegas.
WAT - West Africa Time
Many of the countries in West Africa use the time zone of West Africa Time. It is abbreviated as WAT. WAT is UTC +01:00. Some of the countries using West Africa Time include the following:
WET - Western European Time
WET is the abbreviation for Western European Time. This is UTC 00:00. During daylight savings time, it can be abbreviated as WEDT for Western European Daylight Time or WEST for Western European Summer Time. The following countries use WET:
- United Kingdom
DST - Daylight Savings Time
Many countries observe Daylight Saving Time, which has the abbreviation of DST. This is the practice of moving clocks one hour ahead in the spring to extend daylight hours during convenient times for workers.
Understanding Time Zones Helps You Communicate
When you’re communicating with people from other countries, it’s helpful to know a bit about the time zones, common abbreviations, and which countries are included. This is a small part of understanding other cultures.