- Coordinated Universal Time replaced the use of Greenwich Mean Time (GMT) in 1972. You will often see time zones represented similar to UTC - 5h or GMT - 5h. In this example the (-5h) refers to that time zone being five hours behind UTC or GMT and so forth for the other time zones.
- Although UTC and GMT indicate the same time, UTC is based on the more precise mechanism of time measurement. Nevertheless, both of these time standards are widely used in the world for a similar purpose of time coordination. Definitions of GMT and UTC The abbreviation of GMT stands for Greenwich Mean Time.
- Greenwich Mean Time (GMT) is often interchanged or confused with Coordinated Universal Time (UTC). But GMT is a time zone and UTC is a time standard. The Royal Observatory in the UK.
- UTC and GMT, while they may be the same time zone and time are NOT the same. GMT does exist but is subject to daylight savings. UTC (in military sometimes referred to Zulu Time) is a time constant that is never subject to seasonal time changes.
UTC, Coordinated Universal Time, popularly known as GMT Local time differs from UTC by the number of hours of your timezone. GPS, Global Positioning System time, is the atomic time scale implemented by the atomic clocks in the GPS ground control stations.
Local time is based on time zone and Coordinated Universal Time (UTC). UTC is commonly referred to as International Time, Universal Time (UT), Zulu Time(U.S. military), or Greenwich Mean Time (GMT). GMT was established by international conference in 1884 as International Time.
The earth is divided into 24 time zones, -11 to +12. Each time zone is 1 hour long, or 15° wide in longitude. Greenwich England is, by definition, in the middle of Time Zone 0, the prime meridian. UTC timeis the local time at Greenwich England. Time in other locations will be the UTC time hour plus or minus the local Time Zone. Daylight savings time adds 1 hour to the local standard (real) time.
Twenty four hour time does not use 'am' or 'pm', but courts hours from midnight (0 hours) to 11 pm (23 hours).
AM / PM and 24 Hour Time12 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | am |
0 | 01 | 02 | 03 | 04 | 05 | 06 | 07 | 08 | 09 | 10 | 11 | hours |
12 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | pm |
12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | hours |
Utc And Gmt Time
UNIVERSAL TIME |
Time Around the World
Time zone & local time (Standard)
-11 | -10 | -9 | PST -8 | MST -7 | CST -6 | EST -5 | -4 | -3 | -2 | -1 | UT 0 | +1 | +2 | +3 | +4 | +5 | +6 | +7 | +8 | +9 | +10 | +11 | +12 |
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Utc Time Map
Hours behind (-), or ahead of, UT
Current Utc And Gmt Time
EST - Eastern Standard Time CST - Central Standard Time MST - Mountain Standard Time PST - Pacific Standard Time |
Time Zone Chart (PDF file) 8.5 x 14 inches, 240 kB, color |
Daylight savings time (DST) is used in the summer months in some regions. DST is 1 hour ahead of standard time. There is no consistency between regions as to when DST takes affect, or reverts back to standard (real) time. DST was never practical and will eventually be phased out (obsolete).
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DEFINITIONS
- Atomic clock -- usually multiple clocks that count seconds (average of all clocks in system) based on the frequency of the cesium 133 atom (Cs) which oscillates at 9,192,631,770 Hertz.
- Mean solar time -- a measurement of the Earth's rotation with respect to the 'fictitious' mean sun.
- second -- One second (1 s or 1 sec.) is the duration of 9,192,631,770 periods of radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom (Cs).
- UT -- An abbreviation (for Universal Time) that should be used to show approximation of all the below.
- UT0 -- mean solar time on the Greenwich meridian obtained from direct astronomical observation. The time 00 hours being at Greenwich mean midnight.
- UT1 -- UT0 corrected for polar motion (widely used).
- UT2 -- UT1 corrected for seasonal variation in the Earth's rotation (a smoothed scale that does not reflect the real periodic variations in the Earth's angular position).
- UTC -- civil atomic time scale on or about the Greenwich meridian kept within 0.9 seconds of UT1.
Standard Date Format
Virtually the entire world formats time as Hours:Minutes:Seconds (hours listed before minutes, minutes listed before seconds). The date format Year-Month-Day has become widely accepted as a standard in many countries.
Virtually the entire world formats time as Hours:Minutes:Seconds (hours listed before minutes, minutes listed before seconds). The date format Year-Month-Day has become widely accepted as a standard in many countries.
International Standard ISO 8601,
United States ANSI X3.30 and NIST FIPS 4-1,
Canadian standard CSA Z234.5,
European standard EN 28601,
British standard BS EN 28601.
United States ANSI X3.30 and NIST FIPS 4-1,
Canadian standard CSA Z234.5,
European standard EN 28601,
British standard BS EN 28601.
Year 2000
The United States and many other countries use the Christian Gregorian calendar to mark years. This calendar has become a standard in such worldwide industries as aviation, and international commerce and trade -- however, other calendars do exist.
PublicationsThe United States and many other countries use the Christian Gregorian calendar to mark years. This calendar has become a standard in such worldwide industries as aviation, and international commerce and trade -- however, other calendars do exist.
8' x 10', 192 pages Table of Contents. | Police Radar Handbook A Comprehensive Guide to Speed Measuring Systems - Print Edition - Kindle Edition Jistmeet. | 6' x 9', 84 pages Table of Contents. | Police Radar Operator Error Microwave and Laser Radar Protocols and Results of Improper Use - Print Edition - Kindle Edition - iPad Edition |
Coordinated Universal Time CopRadar.com/utctime |