CVN-71

Military-Nautical Time Charts

Military Time Conversion Charts

The fundamental means of measuring time is the rotation of the earth. The original standard by which all clocks are regulated is furnished from observation of the stars and their relationship to the earth.

The primary unit of time is the "mean solar day." A mean solar day is the average of the "true solar day," which varies slightly in length. There are four times a year the mean and true solar days are equal, by contrast there are also days which time could vary as much as 16 or more minutes. The difference between the mean solar time and true solar time is called the "equation of time."

Whether telling the time via the direct observation of the stars or some other means, precision is important to the military. For the time precision required in navigating and the syncing of mission resources of today's armed forces, greater accuracy was needed. Enter, the atomic clock.

The extreme precision that is required for today's military, time pieces are calibrated using an atomic clock. The Department of Defense's main atomic clock that is used for calibration and to standardize time for the military is located at the United States Naval Observatory in Washington, D.C.

Military Time Zones

Every meridian has its own mean solar time. In order to avoid continual changing of time as one travels east or west standard time zones are introduced. Each time zone is 15 degrees of longitude in width. The difference between adjoining zones is one hour.

Nautical time zones are used by the military to ensure a standardization of time for the forces. Standard military orders would be delivered in Zulu time. Zulu time is the same as "Greenwich Mean Time" or GMT. Depending on the ship or units location on the planet, it will determine the amount of offset required. For example, if the orders were to launch a mission at 1000 Zulu, and your ship was located near Tokyo, Japan in the "India" time zone -- the India time zone is GMT plus nine hours, so you would subtract nine hours from 1000 Zulu, and know your time to launch would be 0100 local time (India).

Nautical-military time zone chart with large city references.
ZoneTime OffsetMajor City
AlphaGMT +1 Paris, France
BravoGMT +2Athens, Greece
CharlieGMT +3Moscow, Russia
DeltaGMT +4 Kabul, Afghanistan¹
EchoGMT +5New Delhi, India
FoxtrotGMT +6Dhaka, Bangladesh
GolfGMT +7Bangkok, Thailand
HotelGMT +8Beijing, China
IndiaGMT +9Tokyo, Japan
KiloGMT +10Sidney, Australia
LimaGMT +11Honiara, Solomon Islands
MikeGMT +12Wellington, New Zealand
NovemberGMT -1Ponta Delgada, Azores
OscarGMT -2Godthaab, Greenland
PapaGMT -3Buenos Aires, Argentina
QuebecGMT -4Halifax, Nova Scotia
RomeoGMT -5New York, NY United States
SierraGMT -6Dallas, TX United States
TangoGMT -7Denver, CO United States
UniformGMT -8Los Angeles, CA United States
VictorGMT -9Juneau, AK United States
WhiskeyGMT -10Honolulu, HI United States
X-RayGMT -11Nome, AK United States
YankeeGMT -12Suva, Fiji
ZuluGMTGreenwich, England

Note 1: Although located in the Delta Time Zone, local time in Afghanistan is GMT +4 hours 30 minutes.

Military Time Conversion

The civilian standard to military time conversion chart.
Military Time Standard Time Military Time Standard Time
0000 Midnight1200 Noon
01001 AM13001 PM
02002 AM14002 PM
03003 AM 15003 PM
04004 AM 16004 PM
05005 AM17005 PM
06006 AM 18006 PM
07007 AM 19007 PM
08008 AM 20008 PM
09009 AM 21009 PM
100010 AM220010 PM
110011 AM 230011 PM

Reading The Message Traffic "Day Time Group"

When message traffic is sent, each message receives a Day Time Group (DTG). The DTG has the day, month, year and time the message is logged. For example, a message's DTG may say, 212200Z May 2013. Broken down, you know the message was logged on May 21, 2013 at 2200 Zulu time.

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