GMT/UTC Time Zone Conversion
Use this page to help you determine local time for an event given in GMT...
 

GMT Definition And Example...

Question: What is Greenwich Mean Time (GMT) and how do I convert GMT to my local time zone?
Answer: Simply put GMT is the time along the Prime Meridian (0 degree longitude) which passes through Greenwich, England. It is the standard time used in the field of astronomy, meteorology and other scientific disciplines around the world. Greenwich mean time was based upon the time at the zero degree meridian that crossed through Greenwich, England. GMT became a world time and date standard because it was used by Britain's Royal Navy and merchant fleet during the nineteenth century
A major source of confusion when using GMT, also know as UTC, to determine a particular phase of the moon is that the date given also follows UTC time. In other words the UTC date may or may not corrlate to your local date. Suppose your local time zone is CDT (Central Daylight Savings Time), and you want to determine the exact time a full moon occurs in August 2003. The full moon for August 2003 occurs Tuesday Aug 12 at 04:49 UTC. Now let us do the math:
  • The Full Moon Occurs at 04:49 UTC on Tuesday August 12, 2003
  • Subtract -5 hours From 04:49 UTC = 11:49 p.m. Central Daylight Savings Time.
  • The Full Moon For the CDT Zone is 11:49 p.m. Monday August 11, 2003
  • Note: It's important to remember that the full moon occurs at a single instance in time. For observers the moon will appear full for at least a day before and a day after the actual event.

    GMT Conversion - A Quick Reference...

    Conversion Table If you are located in the United States, and want to convert from GMT (Greenwich Mean Time) or UTC (Universal Time Coordinate) to your local time then use the following table.

    From the last Sunday in October through the last Saturday in March standard time is noted as Central Standard Time (CST), (EST), (MST) or (PST).
    From the last Sunday in March through the Last Saturday in October daylight savings time is noted as Central Daylight Time (CDT), (EDT), (MDT) or (PDT) which is one hour added to standard time.

    To convert GMT to local time, simply subtract 6 hours off the GMT to get CST, and subtract 5 hours off the GMT to get CDT. Your answer will be in a form of a 24 hour clock which is equivalent to what the military uses. For example, if you want to convert 20:00 GMT which is often written as 20Z to CST, you would subtract 6 hours off and end up with 14:00 hours CST. Since this is in the form of a 24 hour clock you would subtract 12 hours to get 2:00 PM CST.

    Time Zone Offset
    Time
    Zone
    EDT EST or
    CDT
    CST or
    MDT
    MST or
    PDT
    PST
    Offset UTC-4 UTC-5 UTC-6 UTC-7 UTC-8

    North American Time Zones and GMT

    To convert UTC to local time, you have to add or subtract hours from it. For persons west of the zero meridian to the international date line (which includes all of North America), hours are subtracted from UTC to convert to local time. Below is a table showing the number of hours to subtract from local time zones in North America in order to convert UTC to local time. Not all states use daylight savings time in the summer.

    The Time Zones across North America and Pacific from East to West are:

                    Standard  Daylight Savings
                      Time         Time
        Atlantic
        Eastern        EST          EDT
        Central        CST          CDT
        Mountain       MST          MDT
        Pacific        PST          PDT
        Alaska
        Hawaii
    
    Standard time:

        GMT     ATL  EST  CST  MST  PST  ALA  HAW
    difference   -4   -5   -6   -7   -8   -9  -10
        00       8P*  7P*  6P*  5P*  4P*  3P*  2P*
        01       9P*  8P*  7P*  6P*  5P*  4P*  3P*
        02      10P*  9P*  8P*  7P*  6P*  5P*  4P*
        03      11P* 10P*  9P*  8P*  7P*  6P*  5P*
        04      12A  11P* 10P*  9P*  8P*  7P*  6P*
        05       1A  12A  11P* 10P*  9P*  8P*  7P*
        06       2A   1A  12A  11P* 10P*  9P*  8P*
        07       3A   2A   1A  12A  11P* 10P*  9P*
        08       4A   3A   2A   1A  12A  11P* 10P*
        09       5A   4A   3A   2A   1A  12A  11P*
        10       6A   5A   4A   3A   2A   1A  12A
        11       7A   6A   5A   4A   3A   2A   1A
        12       8A   7A   6A   5A   4A   3A   2A
        13       9A   8A   7A   6A   5A   4A   3A
        14      10A   9A   8A   7A   6A   5A   4A
        15      11A  10A   9A   8A   7A   6A   5A
        16      12P  11A  10A   9A   8A   7A   6A
        17       1P  12P  11A  10A   9A   8A   7A
        18       2P   1P  12P  11A  10A   9A   8A
        19       3P   2P   1P  12P  11A  10A   9A
        20       4P   3P   2P   1P  12P  11A  10A
        21       5P   4P   3P   2P   1P  12P  11A
        22       6P   5P   4P   3P   2P   1P  12P
        23       7P   6P   5P   4P   3P   2P   1P
    
    * represents previous day
      (i.e. 03 hours 23 January 93 is 8PM-MST 22 January)
    
    Summertime (Daylight savings time) for those states that observe daylight savings time. For those that do not, use the standard time table all year:

        GMT     EDT  CDT  MDT  PDT
    difference   -4   -5   -6   -7
        00       8P*  7P*  6P*  5P*
        01       9P*  8P*  7P*  6P*
        02      10P*  9P*  8P*  7P*
        03      11P* 10P*  9P*  8P*
        04      12A  11P* 10P*  9P*
        05       1A  12A  11P* 10P*
        06       2A   1A  12A  11P*
        07       3A   2A   1A  12A
        08       4A   3A   2A   1A
        09       5A   4A   3A   2A
        10       6A   5A   4A   3A
        11       7A   6A   5A   4A
        12       8A   7A   6A   5A
        13       9A   8A   7A   6A
        14      10A   9A   8A   7A
        15      11A  10A   9A   8A
        16      12P  11A  10A   9A
        17       1P  12P  11A  10A
        18       2P   1P  12P  11A
        19       3P   2P   1P  12P
        20       4P   3P   2P   1P
        21       5P   4P   3P   2P
        22       6P   5P   4P   3P
        23       7P   6P   5P   4P
    
    * represents previous day
      (i.e. 03 hours 23 June is 9PM-MDT 22 June)
    

    GMT Hour To Zone Conversion...

    UTC uses a 24-hour system of time notation. "1:00 a.m." in UTC is expressed as 0100, pronounced "zero one hundred." Fifteen minutes after 0100 is expressed as 0115; thirty-eight minutes after 0100 is 0138 (usually pronounced "zero one thirty-eight"). The time one minute after 0159 is 0200. The time one minute after 1259 is 1300 (pronounced "thirteen hundred"). This continues until 2359. One minute later is 0000 ("zero hundred"), and the start of a new UTC day.

    UTC GMT EDT EST CDT CST MDT MST PDT PST
    0000 8 PM 7 PM 6 PM 5 PM 4 PM
    0100 9 PM 8 PM 7 PM 6 PM 5 PM
    0200 10 PM 9 PM 8 PM 7 PM 6 PM
    0300 11 PM 10 PM 9 PM 8 PM 7 PM
    0400 Midnight 11 PM 10 PM 9 PM 8 PM
    0500 1 AM Midnight 11 PM 10 PM 9 PM
    0600 2 AM 1 AM Midnight 11 PM 10 PM
    0700 3 AM 2 AM 1 AM Midnight 11 PM
    0800 4 AM 3 AM 2 AM 1 AM Midnight
    0900 5 AM 4 AM 3 AM 2 AM 1 AM
    1000 6 AM 5 AM 4 AM 3 AM 2 AM
    1100 7 AM 6 AM 5 AM 4 AM 3 AM
    1200 8 AM 7 AM 6 AM 5 AM 4 AM
    1300 9 AM 8 AM 7 AM 6 AM 5 AM
    1400 10 AM 9 AM 8 AM 7 AM 6 AM
    1500 11 AM 10 AM 9 AM 8 AM 7 AM
    1600 Noon 11 AM 10 AM 9 AM 8 AM
    1700 1 PM Noon 11 AM 10 AM 9 AM
    1800 2 PM 1 PM Noon 11 AM 10 AM
    1900 3 PM 2 PM 1 PM Noon 11 AM
    2000 4 PM 3 PM 2 PM 1 PM Noon
    2100 5 PM 4 PM 3 PM 2 PM 1 PM
    2200 6 PM 5 PM 4 PM 3 PM 2 PM
    2300 7 PM 6 PM 5 PM 4 PM 3 PM

    World GMT Table...

    GMT time difference for various locations through out the world.

    Zone City or Area Zone Crosses
    GMT-12 Eniwetok
    GMT-11 Samoa
    GMT-10 Hawaii
    GMT-9 Alaska
    GMT-8 PST, Pacific US
    GMT-7 MST, Mountain US
    GMT-6 CST, Central US
    GMT-5 EST, Eastern US
    GMT-4 Atlantic, Canada
    GMT-3 Brazil, Buenos Aries
    GMT-2 Mid-Atlantic
    GMT-1 Cape Verdes
    GMT Greenwich Mean Time, Dublin
    GMT+1 Berlin, Rome
    GMT+2 Israel, Cairo
    GMT+3 Moscow, Kuwait
    GMT+4 Abu Dhabi, Muscat
    GMT+5 Islamabad, Karachi
    GMT+6 Almaty, Dhaka
    GMT+7 Bangkok, Jakarta
    GMT+8 Hong Kong, Beijing
    GMT+9 Tokyo, Osaka
    GMT+10 Sydney, Melbourne, Guam
    GMT+11 Magadan, Soloman Is.
    GMT+12 Fiji, Wellington, Auckland



    Copyright © 2002 By Keith Cooley     - eMail:krcool@hiwaay.net - Return To Keith's Moon Page