Microsoft has received official decree verifying that Tonga will start observing DST on November 6, 2016 at 02:00 hours. DST in Tonga is scheduled to end on January 15, 2017 at 03:00 hours.
Microsoft is preparing an update to Windows which will reflect these changes. We anticipate this update will be made available in the coming months.
Though we plan to release a data update, there is insufficient lead before the time change goes into effect. Therefore, we offer the following guidance temporary workaround until such an update can be properly created, tested, distributed, and installed.
Our official policy statement can be found on the site at http://microsoft.com/time.
Until an update is made available, we recommend our customers to switch to time zone “(UTC+14:00) Kiritimati Island” from November 6, 2016, until an update is available and installed. Selecting this time zone will correctly reflect the time in Tonga.
Once the update is installed, we recommend users to switch back to “(UTC +13:00) Nuku'alofa” as it will properly account for properly account for historical time data for this region.