Military / NATO single-letter time zone names

Markus Kuhn Markus.Kuhn at
Mon Apr 30 17:08:16 UTC 2001

Interesting bit from the new RFC 2822, which supersedes the RFC 822
Internet email header format:

   The form "+0000" SHOULD be used to indicate a time zone at
   Universal Time.  Though "-0000" also indicates Universal Time, it is
   used to indicate that the time was generated on a system that may be
   in a local time zone other than Universal Time and therefore
   indicates that the date-time contains no information about the local
   time zone.


   The 1 character military time zones were defined in a non-standard
   way in [RFC822] and are therefore unpredictable in their meaning.
   The original definitions of the military zones "A" through "I" are
   equivalent to "+0100" through "+0900" respectively; "K", "L", and "M"
   are equivalent to  "+1000", "+1100", and "+1200" respectively; "N"
   through "Y" are equivalent to "-0100" through "-1200" respectively;
   and "Z" is equivalent to "+0000".  However, because of the error in
   [RFC822], they SHOULD all be considered equivalent to "-0000" unless
   there is out-of-band information confirming their meaning.


Markus G. Kuhn, Computer Laboratory, University of Cambridge, UK
Email: mkuhn at,  WWW: <>

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