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 is releasing the below Windows updates in support of this decision. This change is available in the April 2025 Security monthly update, released on April 8, 2025, for all the below listed versions of Windows.
All Windows updates containing this fix have the following release note text:
“Update for the Aysen region in Chile to support the government DST change order in 2025"
The KB article numbers that support this change are listed below:
| Product | KB Article ID |
| Windows 11, version 24H2 | KB5055523 |
| Windows 11, version 23H2 | KB5055528 |
| Windows 11, version 22H2 | KB5055528 |
| Windows 10, version 22H2 | KB5055518 |
| Windows Server 23H2 | KB5055527 |
| Windows Server 2022 | KB5055526 |
| Windows 10 Enterprise LTSC 2019; Windows Server 2019 | KB5055519 |
| Windows 10 Enterprise LTSC 2016; Windows Server 2016 | KB5055521 |
| Windows 10 TH1 | KB5055547 |
| Windows 8.1 | KB5055557 |
All remaining supported Windows versions 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). Please visit Interim guidance for Chile DST changes 2025 for an earlier announcement of this change and more details on how to set a new time zone.
For Microsoft's official policy on DST and time zone changes, please see Daylight saving time help and support. For information on how to update Windows to use the latest global time zone rules, see How to configure daylight saving time for Microsoft Windows operating systems.
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