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Daylight Saving Time & Time Zone Blog
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Interim guidance for British Columbia time zone changes 2026

Naveen_Shankar's avatar
Naveen_Shankar
Icon for Microsoft rankMicrosoft
Aug 07, 2026

Microsoft has made a decision about addressing the new time-related change for British Columbia.

Editor's note October 13, 2026: Microsoft has released an update to address the new time-related change for British Columbia. Please refer to British Columbia 2026 time zone update available now Ea...
Updated Oct 27, 2026
Version 7.0
OzoVei's avatar
OzoVei
Brass Contributor
Oct 14, 2026

More bugs:

  • Timestamps on teams chat messages are off by 1 hour after setting windows to the new BC time zone. This affects the desktop and browser client.
  • Web browser APIs report local time zone is UTC-7 instead of UTC-8 (as seen on sites like https://webbrowsertools.com/timezone)
  • When booking a room resource in Outlook, no rooms appear in the list of rooms. If the meeting is changed to the old time zone, then rooms appear. All user and room mailboxes have already been set to the new time zone, and all working hours for rooms and users are also set to the new time zone.

Can anyone from Microsoft respond and confirm if something is being done about all the bugs?

gregs36's avatar
gregs36
Tin Contributor
Oct 16, 2026

After a bit of digging we found that the primary issue was Edge and WebView2. This caused issues like the 1 hour time shift in Teams and websites that use JavaScript to determine a device's local time. After updating both to 155.0.4283.60 (Official build) and rebooting, most apps seemed to work properly.

  • OzoVei's avatar
    OzoVei
    Brass Contributor
    Oct 16, 2026

    Yes, I see that the latest Edge update today includes an updated icudtl.dat that includes the new timezone mapping. I haven't checked WebView2, but I assume that will include the same. This would address any applications using Edge/WebView, but not applications using the windows bundled ICU libraries. The resource override I described above will work for those other applications (unless they've disabled external ICU resource loading).

    • gregs36's avatar
      gregs36
      Tin Contributor
      Oct 16, 2026

      Not sure if Google Chrome is using the same. It's still not rendering dates correctly after the latest update.

      • OzoVei's avatar
        OzoVei
        Brass Contributor
        Oct 19, 2026

        Chrome ships with its own ICU data. You can either wait for a new Chrome release that has the fixes, or do the system-wide ICU fix I outlined in one of my other comments.