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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?

  • Henry_Shi's avatar
    Henry_Shi
    Icon for Microsoft rankMicrosoft
    Oct 21, 2026

    We’re currently rolling out an update for room booking in Outlook. Please try again after November 1, 2026. Thanks!

    • MrCoBalt's avatar
      MrCoBalt
      Tin Contributor
      Oct 22, 2026

      Hi Henry_Shi​ does this also mean that Places and its Room Finder features, etc will only be fixed after the time zone changes have already gone into effect? I guess we will have to continue to use Yukon/Saskatchewan time zones as fallbacks for our BC & AB staff then, as confusing as that is for everybody when the Mac/Windows side of things is successfully picking the correct time zone for their physical location, but Outlook Calendar and Work Hours needs to be set differently (which it then complains about!) in order to work…

      • OzoVei's avatar
        OzoVei
        Brass Contributor
        Oct 22, 2026

        You can set everything (windows, mailbox, work hours, etc) to the new time zone definition. But then you need users to do the following workaround in order to add rooms to a meeting:

        • Change the meeting's timezone to the old timezone
        • Add the rooms
        • Change the meeting's timezone back to the new timezone

         

        You don't need to save/submit changes in between any of those steps, so you don't have to send out multiple meeting updates or anything like that. You can do it all while creating the meeting.

        It's super annoying and confusing for users, but it does seem to work.

  • 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.

  • gregs36's avatar
    gregs36
    Tin Contributor
    Oct 14, 2026

    We have observed the same. A clear 1 hour difference in Teams vs the local system time even though Teams is configured to use system time.

    In addition, most desktops in our org are still in the old time zone even though the new one is available and "Detect time zone" is on.  Turning that setting off and on again prompts the user to use the new time zone.