Introducing New Windows Time Zones

Our mission at Microsoft is to empower every person and every organization on the planet to achieve more. In over 20 years of committed diversity and inclusion efforts, we’ve learned that diversity is not a finite goal; it is a journey that requires constant self-assessment and recommitment.

As we continuously strive to make Windows usable by anyone, anywhere in this world, we are planning to release a Windows Update on June 14th 2016 which will introduce 16 new time zones. Once the update is installed, we recommend users in these regions start using these new time zones on their Windows devices. Doing so will not only properly account for historical time data but also ensure DST transitions take effect appropriately if applicable.

1. Criteria for Creating New Time Zones in Windows

A new Windows time zone entry will be created when a country/region (including dependencies), or a first-order administrative division of a country/region (state, province, department, etc.), has a separate and distinct history of UTC offsets and DST rules from existing time zone entries. Additionally, a smaller geographic area (county, city, etc.) qualifies for a new Windows time zone entry when its current UTC offset and DST rule combination is not provided by another Windows time zone entry.

2. New Time Zones

The following time zones have been added, either because they are currently unrepresented, or because they have a unique history of changes in recent years.

2.1. Aleutian Islands, Alaska

ID / Key: Aleutian Standard Time
Display Name: (UTC-10:00) Aleutian Islands

2.2. Marquesas Islands

ID / Key: Marquesas Standard Time
Display Name: (UTC-09:30) Marquesas Islands

2.3. UTC-9

ID / Key: UTC-09
Display Name: (UTC-09:00) Coordinated Universal Time-09
Places Used: Gambier Islands

2.4. UTC-8

ID / Key: UTC-08
Display Name: (UTC-08:00) Coordinated Universal Time-08
Places Used: Pitcairn Islands; Tungsten, Canada; Clarion Island, Mexico; Clipperton Island

2.5. Cuba

ID / Key: Cuba Standard Time
Display Name: (UTC-05:00) Havana

2.6. Turks & Caicos Islands

ID / Key: Turks And Caicos Standard Time
Display Name: (UTC-04:00) Turks and Caicos

2.7. St. Pierre and Miquelon

ID / Key: Saint Pierre Standard Time
Display Name: (UTC-03:00) Saint Pierre and Miquelon

2.8. Tocantins, Brazil

ID / Key: Tocantins Standard Time
Display Name: (UTC-03:00) Araguaina

2.9. West Bank and Gaza

ID / Key: West Bank Standard Time
Display Name: (UTC+02:00) Gaza, Hebron

2.10. Hovd, Mongolia

ID / Key: W. Mongolia Standard Time
Display Name: (UTC+07:00) Hovd

2.11. Tomsk, Russia

ID / Key: Tomsk Standard Time
Display Name: (UTC+07:00) Tomsk

2.12. Eucla, Australia

ID / Key: Aus Central W. Standard Time
Display Name: (UTC+08:45) Eucla

2.13. Bougainville Island

ID / Key: Bougainville Standard Time
Display Name: (UTC+11:00) Bougainville Island

2.14. Norfolk Island

ID / Key: Norfolk Standard Time
Display Name: (UTC+11:00) Norfolk Island

2.15. Lord Howe Island, Australia

ID / Key: Lord Howe Standard Time
Display Name: (UTC+10:30) Lord Howe Island

2.16. Chatham Islands, New Zealand

ID / Key: Chatham Island Standard Time
Display Name: (UTC+12:45) Chatham Islands


3. Display Name Changes to Existing Time Zones

These changes improve the usability of the existing time zone entries in Windows.

3.1. Morocco

ID / Key: Morocco Standard Time
Old Display Name: (UTC) Casablanca
New Display Name: (UTC+00:00) Casablanca

3.2. United Kingdom

ID / Key: GMT Standard Time
Old Display Name: (UTC) Dublin, Edinburgh, Lisbon, London
New Display Name: (UTC+00:00) Dublin, Edinburgh, Lisbon, London

3.3. Iceland

ID / Key: Greenwich Standard Time
Old Display Name: (UTC) Monrovia, Reykjavik
New Display Name: (UTC+00:00) Monrovia, Reykjavik

3.4. Moldova

ID / Key: E. Europe Standard Time
Old Display Name: (UTC+02:00) E. Europe
New Display Name: (UTC+02:00) Chisinau
Comments: Due to differences in daylight saving time rules, this entry should only be used in Moldova. Other locations that use Eastern European Time should choose one of the following time zone entries instead:(UTC+02:00) Athens, Bucharest(UTC+02:00) Beirut(UTC+02:00) Cairo(UTC+02:00) Damascus(UTC+02:00) Helsinki, Kyiv, Riga, Sofia, Tallinn, Vilnius(UTC+02:00) Istanbul(UTC+02:00) Tripoli


4. Other data corrections

Apart from the changes described above, we have improved historical data accuracy of 25 existing time zone entries in Windows.