Military

time zone A time zone is an area which observes a uniform standard time for legal, commercial and social purposes. Time zones tend to follow the boundaries between countries and their subdivisions instead of strictly following longitude, because i ...

s are defined in the ACP 121(I) standard, which is used by the

armed forces A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. It is typically authorized and maintained by a sovereign state, with its members identifiable by their distinct ...

for Australia, Canada, New Zealand, the United Kingdom, the United States, and many other nations. The names are identical to the

NATO phonetic alphabet The (International) Radiotelephony Spelling Alphabet, commonly known as the NATO phonetic alphabet, is the most widely used set of clear code words for communicating the letters of the Roman alphabet, technically a ''radiotelephonic spellin ...

. Going east from the

prime meridian A prime meridian is an arbitrary meridian (a line of longitude) in a geographic coordinate system at which longitude is defined to be 0°. Together, a prime meridian and its anti-meridian (the 180th meridian in a 360°-system) form a great ...

at Greenwich, letters "Alfa" to "Mike" (skipping "J", see below) represent the 12 time zones with positive

UTC offset The UTC offset is the difference in hours and minutes between Coordinated Universal Time (UTC) and local solar time, at a particular place. This difference is expressed with respect to UTC and is generally shown in the format , , or . So if the tim ...

s until reaching the

international Date Line The International Date Line (IDL) is an internationally accepted demarcation on the surface of Earth, running between the South and North Poles and serving as the boundary between one calendar day and the next. It passes through the Pacific ...

. Going west from Greenwich, letters "November" to "Yankee" represent zones with negative offsets. The letters are typically used in conjunction with military time. For example, 6:00 a.m. in zone UTC−5 is written "0600R" and spoken "zero six hundred Romeo". The letter "J" ("Juliet"), originally skipped, may be used to indicate the observer's local time. The letter "Z" ("Zulu") indicates

Coordinated Universal Time Coordinated Universal Time or UTC is the primary time standard by which the world regulates clocks and time. It is within about one second of mean solar time (such as UT1) at 0° longitude (at the IERS Reference Meridian as the currently ...

(UTC).

History

Sandford Fleming Sir Sandford Fleming (January 7, 1827 – July 22, 1915) was a Scottish Canadian engineer and inventor. Born and raised in Scotland, he emigrated to colonial Canada at the age of 18. He promoted worldwide standard time zones, a prime meridian ...

devised a system assigning the letters A-Y excluding J to 1-hour time zones, which may have been the inspiration for the system. The standard was first distributed by

NATO The North Atlantic Treaty Organization (NATO, ; french: Organisation du traité de l'Atlantique nord, ), also called the North Atlantic Alliance, is an intergovernmental military alliance between 30 member states – 28 European and two No ...

as a note in 1950. The note states "This method is based on the systems in use in the Armed Forces of these countries and the United States".

References

Military/NATO/Letter time zones

External links

discussion on the tz mailing list {{UTC time offsets *

History

See also

References

External links