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Timezone Abbreviations Reference: Complete Guide

Overview

This comprehensive reference lists all major timezone abbreviations used worldwide, including their UTC offsets, daylight saving time (DST) rules, and common usage regions. Use this guide to quickly lookup timezone information when working with timestamps and scheduling.

Quick Lookup

Most Common Timezones

AbbreviationFull NameUTC Offset (Standard)DST OffsetRegions
UTCCoordinated Universal Time+00:00No DSTWorldwide Standard
GMTGreenwich Mean Time+00:00No DSTUK, West Africa
ESTEastern Standard Time-05:00EDT -04:00US East Coast
PSTPacific Standard Time-08:00PDT -07:00US West Coast
CSTCentral Standard Time-06:00CDT -05:00US Central
MSTMountain Standard Time-07:00MDT -06:00US Mountain
CETCentral European Time+01:00CEST +02:00Central Europe
ISTIndia Standard Time+05:30No DSTIndia
JSTJapan Standard Time+09:00No DSTJapan
AESTAustralian Eastern Standard+10:00AEDT +11:00Eastern Australia

By UTC Offset

UTC -12:00 to -09:00

UTC -12:00

  • BIT - Baker Island Time
    • Region: Baker Island, Howland Island
    • DST: No DST
    • Notes: Uninhabited territories

UTC -11:00

  • NUT - Niue Time
    • Region: Niue
    • DST: No DST
  • SST - Samoa Standard Time
    • Region: American Samoa
    • DST: No DST

UTC -10:00

  • HST - Hawaii-Aleutian Standard Time
    • Region: Hawaii (most)
    • DST: No DST
    • Notes: Most of Hawaii doesn't observe DST
  • HAST - Hawaii-Aleutian Standard Time
    • Region: Aleutian Islands
    • DST: HADT -09:00
  • TAHT - Tahiti Time
    • Region: French Polynesia
    • DST: No DST

UTC -09:00

  • AKST - Alaska Standard Time
    • Region: Alaska
    • DST: AKDT -08:00
  • HADT - Hawaii-Aleutian Daylight Time
    • Region: Aleutian Islands (Summer)
    • DST: Daylight variant of HAST

UTC -08:00 to -05:00 (Americas)

UTC -08:00

  • PST - Pacific Standard Time
    • Region: US/Canada West Coast (Winter)
    • DST: PDT -07:00
    • Major Cities: Los Angeles, San Francisco, Seattle, Vancouver
  • AKDT - Alaska Daylight Time
    • Region: Alaska (Summer)
    • DST: Daylight variant of AKST

UTC -07:00

  • MST - Mountain Standard Time
    • Region: US/Canada Mountain (Winter)
    • DST: MDT -06:00
    • Major Cities: Denver, Calgary, Phoenix (no DST)
  • PDT - Pacific Daylight Time
    • Region: US/Canada West Coast (Summer)
    • DST: Daylight variant of PST
  • PNT - Phoenix Time
    • Region: Arizona (most)
    • DST: No DST
    • Notes: Arizona doesn't observe DST (except Navajo Nation)

UTC -06:00

  • CST - Central Standard Time
    • Region: US/Canada Central (Winter)
    • DST: CDT -05:00
    • Major Cities: Chicago, Mexico City, Winnipeg
  • MDT - Mountain Daylight Time
    • Region: US/Canada Mountain (Summer)
    • DST: Daylight variant of MST
  • GALT - Galapagos Time
    • Region: Galapagos Islands
    • DST: No DST

UTC -05:00

  • EST - Eastern Standard Time
    • Region: US/Canada East Coast (Winter)
    • DST: EDT -04:00
    • Major Cities: New York, Toronto, Miami
  • CDT - Central Daylight Time
    • Region: US/Canada Central (Summer)
    • DST: Daylight variant of CST
  • COT - Colombia Time
    • Region: Colombia
    • DST: No DST
  • PET - Peru Time
    • Region: Peru
    • DST: No DST

UTC -04:00 to -01:00 (Atlantic & South America)

UTC -04:00

  • EDT - Eastern Daylight Time
    • Region: US/Canada East Coast (Summer)
    • DST: Daylight variant of EST
  • AST - Atlantic Standard Time
    • Region: Atlantic Canada, Caribbean
    • DST: ADT -03:00 (some regions)
  • BOT - Bolivia Time
    • Region: Bolivia
    • DST: No DST
  • VET - Venezuelan Standard Time
    • Region: Venezuela
    • DST: No DST

UTC -03:30

  • NST - Newfoundland Standard Time
    • Region: Newfoundland, Canada
    • DST: NDT -02:30
    • Notes: Unique half-hour offset

UTC -03:00

  • ADT - Atlantic Daylight Time
    • Region: Atlantic Canada (Summer)
    • DST: Daylight variant of AST
  • ART - Argentina Time
    • Region: Argentina
    • DST: No DST (since 2009)
  • BRT - Brasília Time
    • Region: Eastern Brazil
    • DST: BRST -02:00 (varies by year)
  • FKST - Falkland Islands Summer Time
    • Region: Falkland Islands
    • DST: Daylight variant
  • UYT - Uruguay Time
    • Region: Uruguay
    • DST: No DST currently

UTC -02:00

  • BRST - Brasília Summer Time
    • Region: Eastern Brazil (Summer)
    • DST: Daylight variant of BRT
  • GST - South Georgia Time
    • Region: South Georgia Island
    • DST: No DST

UTC -01:00

  • AZOT - Azores Standard Time
    • Region: Azores, Portugal
    • DST: AZOST +00:00
  • CVT - Cape Verde Time
    • Region: Cape Verde
    • DST: No DST
  • EGT - Eastern Greenland Time
    • Region: Eastern Greenland
    • DST: EGST +00:00

UTC +00:00 to +03:00 (Europe & Africa)

UTC +00:00

  • GMT - Greenwich Mean Time
    • Region: UK, Ireland (Winter)
    • DST: BST +01:00
    • Notes: Reference meridian
  • UTC - Coordinated Universal Time
    • Region: International Standard
    • DST: No DST
    • Notes: Scientific time standard
  • WET - Western European Time
    • Region: Portugal, Iceland (Winter)
    • DST: WEST +01:00

UTC +01:00

  • CET - Central European Time
    • Region: Most of Western Europe (Winter)
    • DST: CEST +02:00
    • Major Cities: Paris, Berlin, Rome, Madrid
  • BST - British Summer Time
    • Region: UK, Ireland (Summer)
    • DST: Daylight variant of GMT
  • WEST - Western European Summer Time
    • Region: Portugal (Summer)
    • DST: Daylight variant of WET
  • WAT - West Africa Time
    • Region: West Central Africa
    • DST: No DST
    • Countries: Nigeria, Niger, Chad

UTC +02:00

  • CEST - Central European Summer Time
    • Region: Most of Western Europe (Summer)
    • DST: Daylight variant of CET
  • EET - Eastern European Time
    • Region: Eastern Europe (Winter)
    • DST: EEST +03:00
    • Countries: Greece, Romania, Finland
  • SAST - South African Standard Time
    • Region: South Africa, Botswana
    • DST: No DST
  • CAT - Central Africa Time
    • Region: Central Africa
    • DST: No DST
    • Countries: Zimbabwe, Zambia, Malawi
  • IST - Israel Standard Time
    • Region: Israel
    • DST: IDT +03:00

UTC +03:00

  • EEST - Eastern European Summer Time
    • Region: Eastern Europe (Summer)
    • DST: Daylight variant of EET
  • EAT - East Africa Time
    • Region: East Africa
    • DST: No DST
    • Countries: Kenya, Tanzania, Ethiopia
  • MSK - Moscow Standard Time
    • Region: Western Russia
    • DST: No DST (since 2014)
  • AST - Arabia Standard Time
    • Region: Saudi Arabia, Iraq, Kuwait
    • DST: No DST
  • SYOT - Syowa Time
    • Region: Antarctica (Syowa Station)
    • DST: No DST

UTC +03:30 to +06:00 (Middle East & Central Asia)

UTC +03:30

  • IRST - Iran Standard Time
    • Region: Iran
    • DST: IRDT +04:30
    • Notes: Unique half-hour offset

UTC +04:00

  • GET - Georgia Standard Time
    • Region: Georgia
    • DST: No DST
  • AMT - Armenia Time
    • Region: Armenia
    • DST: No DST
  • AZT - Azerbaijan Time
    • Region: Azerbaijan
    • DST: No DST
  • GST - Gulf Standard Time
    • Region: UAE, Oman
    • DST: No DST
  • MUT - Mauritius Time
    • Region: Mauritius
    • DST: No DST

UTC +04:30

  • AFT - Afghanistan Time
    • Region: Afghanistan
    • DST: No DST
    • Notes: Unique half-hour offset

UTC +05:00

  • PKT - Pakistan Standard Time
    • Region: Pakistan
    • DST: No DST
  • UZT - Uzbekistan Time
    • Region: Uzbekistan
    • DST: No DST
  • YEKT - Yekaterinburg Time
    • Region: West Siberia, Russia
    • DST: No DST
  • MAWT - Mawson Time
    • Region: Antarctica (Mawson Station)
    • DST: No DST

UTC +05:30

  • IST - India Standard Time
    • Region: India, Sri Lanka
    • DST: No DST
    • Notes: Unique half-hour offset
    • Population: Over 1.4 billion people

UTC +05:45

  • NPT - Nepal Time
    • Region: Nepal
    • DST: No DST
    • Notes: Unique 45-minute offset

UTC +06:00

  • BST - Bangladesh Standard Time
    • Region: Bangladesh
    • DST: No DST
  • BTT - Bhutan Time
    • Region: Bhutan
    • DST: No DST
  • KGT - Kyrgyzstan Time
    • Region: Kyrgyzstan
    • DST: No DST
  • OMST - Omsk Standard Time
    • Region: Omsk, Russia
    • DST: No DST

UTC +06:30 to +09:00 (Asia)

UTC +06:30

  • MMT - Myanmar Time
    • Region: Myanmar (Burma)
    • DST: No DST
    • Notes: Unique half-hour offset
  • CCT - Cocos Islands Time
    • Region: Cocos Islands
    • DST: No DST

UTC +07:00

  • ICT - Indochina Time
    • Region: Vietnam, Cambodia, Laos, Thailand
    • DST: No DST
  • WIB - Western Indonesian Time
    • Region: Western Indonesia (Jakarta)
    • DST: No DST
  • KRAT - Krasnoyarsk Time
    • Region: Krasnoyarsk, Russia
    • DST: No DST
  • NOVT - Novosibirsk Time
    • Region: Novosibirsk, Russia
    • DST: No DST

UTC +08:00

  • CST - China Standard Time
    • Region: Mainland China, Taiwan
    • DST: No DST
    • Notes: Single timezone for all of China
  • HKT - Hong Kong Time
    • Region: Hong Kong
    • DST: No DST
  • SGT - Singapore Time
    • Region: Singapore
    • DST: No DST
  • PHT - Philippine Time
    • Region: Philippines
    • DST: No DST
  • WITA - Central Indonesian Time
    • Region: Central Indonesia (Bali)
    • DST: No DST
  • MYT - Malaysia Time
    • Region: Malaysia
    • DST: No DST
  • AWST - Australian Western Standard Time
    • Region: Western Australia
    • DST: No DST (most of WA)
  • IRKT - Irkutsk Time
    • Region: Irkutsk, Russia
    • DST: No DST

UTC +08:45

  • ACWST - Australian Central Western Standard Time
    • Region: Eucla, Western Australia
    • DST: No DST
    • Notes: Unique 45-minute offset, very small population

UTC +09:00

  • JST - Japan Standard Time
    • Region: Japan
    • DST: No DST
  • KST - Korea Standard Time
    • Region: South Korea, North Korea
    • DST: No DST
  • WIT - Eastern Indonesian Time
    • Region: Eastern Indonesia
    • DST: No DST
  • TLT - Timor Leste Time
    • Region: East Timor
    • DST: No DST
  • YAKT - Yakutsk Time
    • Region: Yakutsk, Russia
    • DST: No DST

UTC +09:30 to +12:00 (Oceania)

UTC +09:30

  • ACST - Australian Central Standard Time
    • Region: South Australia, Northern Territory
    • DST: ACDT +10:30 (SA only)
    • Major Cities: Adelaide

UTC +10:00

  • AEST - Australian Eastern Standard Time
    • Region: Eastern Australia (Winter)
    • DST: AEDT +11:00 (most areas)
    • Major Cities: Sydney, Melbourne, Brisbane
  • ACDT - Australian Central Daylight Time
    • Region: South Australia (Summer)
    • DST: Daylight variant of ACST
  • ChST - Chamorro Standard Time
    • Region: Guam, Northern Mariana Islands
    • DST: No DST
  • PGT - Papua New Guinea Time
    • Region: Papua New Guinea
    • DST: No DST
  • VLAT - Vladivostok Time
    • Region: Vladivostok, Russia
    • DST: No DST

UTC +10:30

  • LHST - Lord Howe Standard Time
    • Region: Lord Howe Island
    • DST: LHDT +11:00
    • Notes: Unique half-hour offset and 30-minute DST shift

UTC +11:00

  • AEDT - Australian Eastern Daylight Time
    • Region: Eastern Australia (Summer)
    • DST: Daylight variant of AEST
  • NCT - New Caledonia Time
    • Region: New Caledonia
    • DST: No DST
  • SBT - Solomon Islands Time
    • Region: Solomon Islands
    • DST: No DST
  • VUT - Vanuatu Time
    • Region: Vanuatu
    • DST: No DST
  • MAGT - Magadan Time
    • Region: Magadan, Russia
    • DST: No DST

UTC +12:00

  • NZST - New Zealand Standard Time
    • Region: New Zealand (Winter)
    • DST: NZDT +13:00
  • FJT - Fiji Time
    • Region: Fiji
    • DST: FJST +13:00 (some years)
  • GILT - Gilbert Island Time
    • Region: Kiribati (Gilbert Islands)
    • DST: No DST
  • PETT - Kamchatka Time
    • Region: Kamchatka, Russia
    • DST: No DST
  • TVT - Tuvalu Time
    • Region: Tuvalu
    • DST: No DST
  • WFT - Wallis and Futuna Time
    • Region: Wallis and Futuna
    • DST: No DST

UTC +12:45 to +14:00 (Far East Pacific)

UTC +12:45

  • CHAST - Chatham Standard Time
    • Region: Chatham Islands, New Zealand
    • DST: CHADT +13:45
    • Notes: Unique 45-minute offset

UTC +13:00

  • NZDT - New Zealand Daylight Time
    • Region: New Zealand (Summer)
    • DST: Daylight variant of NZST
  • PHOT - Phoenix Island Time
    • Region: Phoenix Islands, Kiribati
    • DST: No DST
  • TOT - Tonga Time
    • Region: Tonga
    • DST: TOST +14:00 (some years)
  • TKT - Tokelau Time
    • Region: Tokelau
    • DST: No DST
  • FJST - Fiji Summer Time
    • Region: Fiji (Summer, varies)
    • DST: Daylight variant of FJT

UTC +13:45

  • CHADT - Chatham Daylight Time
    • Region: Chatham Islands (Summer)
    • DST: Daylight variant of CHAST

UTC +14:00

  • LINT - Line Islands Time
    • Region: Line Islands, Kiribati
    • DST: No DST
    • Notes: One of the earliest timezones to see the new day
  • TOST - Tonga Summer Time
    • Region: Tonga (Summer, varies)
    • DST: Daylight variant of TOT

Special Cases & Notes

Military Time Zones

Military uses single-letter timezone codes:

LetterUTC OffsetName
Z+00:00Zulu Time (UTC)
A+01:00Alpha
B+02:00Bravo
C+03:00Charlie
D+04:00Delta
E+05:00Echo
F+06:00Foxtrot
G+07:00Golf
H+08:00Hotel
I+09:00India
K+10:00Kilo
L+11:00Lima
M+12:00Mike
N-01:00November
O-02:00Oscar
P-03:00Papa
Q-04:00Quebec
R-05:00Romeo
S-06:00Sierra
T-07:00Tango
U-08:00Uniform
V-09:00Victor
W-10:00Whiskey
X-11:00X-ray
Y-12:00Yankee

Note: Letter J is not used to avoid confusion with local time.

Ambiguous Abbreviations

Some timezone abbreviations are used for multiple regions:

  • CST: Central Standard Time (US) OR China Standard Time OR Cuba Standard Time
  • IST: India Standard Time OR Israel Standard Time OR Irish Standard Time
  • AST: Atlantic Standard Time OR Arabia Standard Time
  • BST: British Summer Time OR Bangladesh Standard Time
  • GST: Gulf Standard Time OR South Georgia Time

Best Practice: Always use full timezone names or IANA timezone identifiers to avoid confusion.

Deprecated Timezones

Some timezone abbreviations are no longer officially used:

  • PST8PDT → Use America/Los_Angeles
  • EST5EDT → Use America/New_York
  • CST6CDT → Use America/Chicago

No DST Regions

Major regions that don't observe Daylight Saving Time:

  • Asia: Most of Asia (China, Japan, India, etc.)
  • Africa: All of Africa
  • Central/South America: Most countries
  • Oceania: Queensland (Australia), Northern Territory (Australia)
  • North America: Arizona (most), Hawaii, Saskatchewan

DST Transition Rules

United States & Canada

  • Start: Second Sunday in March at 2:00 AM local time
  • End: First Sunday in November at 2:00 AM local time
  • Shift: Clocks move forward 1 hour in spring, back 1 hour in fall

European Union

  • Start: Last Sunday in March at 1:00 AM UTC
  • End: Last Sunday in October at 1:00 AM UTC
  • Shift: Clocks move forward 1 hour in spring, back 1 hour in fall
  • Note: EU voted to abolish DST, but implementation is pending

Australia

  • Start: First Sunday in October at 2:00 AM local time
  • End: First Sunday in April at 3:00 AM local time
  • Regions: NSW, VIC, SA, TAS, ACT (QLD, NT, WA don't observe)

New Zealand

  • Start: Last Sunday in September at 2:00 AM local time
  • End: First Sunday in April at 3:00 AM local time

IANA Timezone Database

For programming, use IANA timezone identifiers instead of abbreviations:

Recommended Format

Continent/City

Examples

AbbreviationIANA IdentifierRecommended
EST/EDTAmerica/New_York✅
PST/PDTAmerica/Los_Angeles✅
CET/CESTEurope/Paris✅
JSTAsia/Tokyo✅
AEST/AEDTAustralia/Sydney✅
ISTAsia/Kolkata✅ (India)
ISTAsia/Jerusalem✅ (Israel)

Code Examples

// JavaScript - Use IANA identifiers
const date = new Date();
const nyTime = date.toLocaleString('en-US', { timeZone: 'America/New_York' });
const tokyoTime = date.toLocaleString('en-US', { timeZone: 'Asia/Tokyo' });

# Python - Use pytz with IANA identifiers
from datetime import datetime
import pytz

ny_tz = pytz.timezone('America/New_York')
tokyo_tz = pytz.timezone('Asia/Tokyo')

ny_time = datetime.now(ny_tz)
tokyo_time = datetime.now(tokyo_tz)

Best Practices

When Working with Timezones

  1. Always use UTC internally - Convert to local timezones only for display
  2. Use IANA identifiers - More precise than abbreviations
  3. Never hardcode offsets - DST rules change
  4. Store timezone info with timestamps - Avoid ambiguity
  5. Be aware of DST transitions - Can cause duplicate or missing hours
  6. Test edge cases - Leap seconds, DST transitions, timezone changes

Common Pitfalls

❌ Avoid:

  • Using timezone abbreviations in code (use IANA identifiers)
  • Assuming all US states observe DST
  • Forgetting that China has only one timezone
  • Hardcoding DST transition dates
  • Ignoring half-hour and 45-minute offsets

✅ Do:

  • Use timezone-aware datetime objects
  • Leverage timezone libraries (pytz, moment-timezone, etc.)
  • Always include timezone information
  • Test with different timezones
  • Handle DST transitions gracefully

Related Resources