Military time zones

Zulu is UTC. Alpha is UTC+1. Yankee is UTC−12. These letters are offsets, not IANA zones, so they ignore daylight saving.

Letter, name, and offset from UTC
LetterNameOffset
AAlphaUTC+1
BBravoUTC+2
CCharlieUTC+3
DDeltaUTC+4
EEchoUTC+5
FFoxtrotUTC+6
GGolfUTC+7
HHotelUTC+8
IIndiaUTC+9
KKiloUTC+10
LLimaUTC+11
MMikeUTC+12
NNovemberUTC-1
OOscarUTC-2
PPapaUTC-3
QQuebecUTC-4
RRomeoUTC-5
SSierraUTC-6
TTangoUTC-7
UUniformUTC-8
VVictorUTC-9
WWhiskeyUTC-10
XX-rayUTC-11
YYankeeUTC-12
ZZuluUTC

Juliet (J) is omitted on purpose. In radio use it means the speaker's local civil time, not a fixed offset.

How the letters work

Zulu

Z is UTC, all year

NATO letter zones are whole-hour offsets from UTC. They do not follow daylight saving. A ship on Zulu stays on UTC while London is on BST.

East and west

Alpha to Mike, November to Yankee

A through M (skipping J) run east, UTC+1 to UTC+12. N through Y run west, UTC-1 to UTC-12. The names are the NATO spelling alphabet.

Civil names

People still say GMT

Civil abbreviations such as GMT, EST, and JST live on a separate list. They can clash. These letters do not.