Interim guidance for Chile DST changes 2025

Microsoft

Apr 01, 2025

Editor’s note 4.08.2025: Microsoft has released all Windows updates applicable to address Chile time zone changes in 2025.04 B Security Update. Here's a new post published about it: Chile 2025 Time Zone update available now

On March 20, 2025, the Chile government made an official announcement that the Aysén Region in Chile would permanently stay in Daylight Saving Time (DST) or UTC-3.

The impact of this change is as follows:

Clocks will not advance by 60 minutes at 12:00 A.M. (midnight) on April 6, 2025, for the Chile Aysén Region time zone
The Chile Aysén Region time zone will shift to the new time zone America/Coyhaique at UTC-3 for the foreseeable future and will be referred to as Magallanes Standard Time year-round

Microsoft plans to release an update to support this change. However, we require sufficient time to properly build, test, and release such an update for all platforms before the change goes into effect. See How Windows manages time zone changes to better understand the complexities of this process.

The following platforms will receive an update to support this time zone change as part of the April 2025 Windows security update:

Windows 11, version 24H2
Windows Server 23H2
Windows 11, version 22H2 and version 23H2
Windows 10, version 22H2; Windows 10, version 21H2
Windows Server 2022
Windows 10 Enterprise LTSC 2019; Windows Server 2019
Windows 10 Enterprise LTSC 2016; Windows Server 2016
Windows 10 Enterprise 2015 LTSB

For Devices on remaining versions of Windows i.e., Windows Server 2012, Windows 7 SP1, Windows Server 2008 R2 SP1, and Windows Server 2008 SP2 - will have to manually set a new time zone setting to “(UTC-3) Punta Arenas” on April 6, 2025, at 12:00 A.M. (midnight).

Interim guidance

Starting on April 6,12:00 AM and until you take the April 2025 Windows security update, we recommend that affected organizations with devices in the Chile Aysén Region use the following workaround: set a different time zone to reflect the correct local time.

Important

Regardless of April 2025 Windows Security Update, this is a required step for devices on the following versions: Windows Server 2012, Windows 7 SP1, Windows Server 2008 R2 SP1, and Windows Server 2008 SP2 to sync to correct time settings.

Set a new time zone on the devices

Microsoft recommends that users set the time zone on their devices to “(UTC-3) Punta Arenas” on April 6, 2025, at 12:00 A.M. (midnight). Selecting this time zone will ensure that devices reflect the correct local time, i.e., Magallanes Standard time. (Note: Events that have occurred in the past, before the update, will not show correctly.)

This can be done in one of the two ways:

Select the Windows logo key, type "time zone", and select Change the time zone. From the time zone dropdown, select “(UTC-3) Punta Arenas”.
Navigate to Control Panel > Date and Time > Change time zone. From the time zone dropdown, select “(UTC-3) Punta Arenas”. Select OK to apply the change.