List of military time zones

This is a list of time zones as used by the U.S. military, Chinese military and others. The names are based on the NATO phonetic alphabet (with two spelling changes: Alpha for "Alfa", Juliet for "Juliett").

Going east from the prime meridian at Greenwich, letters Alpha through to Mike (skipping "J", see below) are used for the 12 time zones with mainly positive UTC offsets until reaching the International Date Line. Going west from Greenwich, letters November through to Yankee are used for zones with negative time offsets.

The system originates with Nathaniel Bowditch's 1802 American Practical Navigator where time zones were labelled with letters: the letter "J" was skipped to avoid confusion with "I" (as was the custom of the time) and because some alphabets don't have one (such as Cyrillic). The militaries of Australia, Canada, New Zealand, the United Kingdom, and the United States (also known as Five Eyes) use Allied Communications Publication (ACP) 121 as their reference for the time zone designators.

The letter J ("Juliet"), originally skipped, may now be used to indicate the observer's local time. This is not an international standard, and many locations/fields may not recognize such use.

The letter Z ("Zulu") indicates Greenwich Mean Time (GMT) or Coordinated Universal Time (see UTC±00:00).

They are used in conjunction with military time: for instance, 6:00 a.m. in zone UTC−5 is written "0600R" and spoken "zero six hundred Romeo".

...
Wikipedia