Timezones are incorrect: For some reasons outlook on mac thinks Alberta time is UTC -7, but outlook web thinks its UTC -6

Rahul Bhardwaj 0 Reputation points
2026-11-04T00:35:51.56+00:00

For some reasons outlook on mac thinks Alberta time is UTC -7, but outlook web thinks its UTC -6. This is with the same new Mountain Time (Alberta) selected as timezone. 

Outlook | Web | Outlook on the web for business | Calendar

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  1. Kai-Ex 2,480 Reputation points Microsoft External Staff Moderator
    2026-11-04T01:06:28.7666667+00:00

    Dear Rahul Bhardwaj,

    I understand the confusion. Based on your description, this may be a difference in how Outlook for Mac and Outlook on the web display the Mountain Time (Alberta) time zone. Alberta observes Daylight Saving Time, which means the effective offset changes during the year:

    • MST (Mountain Standard Time) = UTC-7
    • MDT (Mountain Daylight Time) = UTC-6

    Effective November 1, 2026, users in the Canadian provinces of British Columbia, Alberta, and Manitoba will stay on permanent Daylight Saving Time (DST) and stop observing DST changes. Users will need to change their settings to the following time zone: Alberta (UTC-06:00) Mountain Time (Alberta). For reference: Outlook Time Zone Changes for British Columbia, Alberta, and Manitoba

    First of all, I would recommend following the suggestions provided in the AI response and:

    • Verify that Outlook for Mac, Outlook on the web, and macOS Date & Time settings are all configured to the same Mountain Time (Alberta) time zone.
    • Ensure both Outlook for Mac and macOS are fully up to date.

    Then, Outlook users impacted by the time zone change will need to do the following:

    • Change their Outlook calendar time zone to the appropriate new time zone. For reference: Outlook Time Zone Changes for British Columbia, Alberta, and Manitoba
    • Update upcoming calendar events and meetings so they use the new time zone.
    • Specifically verify that events scheduled in advance and recurring meetings that continue beyond November 1, 2026 are reflecting the new time zone.

    Thank you for your patience and understanding. If you have any questions or if I have misunderstood anything, please feel free to reach out. I'm looking forward to your update

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  2. AI answer

    2026-11-04T00:36:37.8466667+00:00

    Update Outlook for Mac to build 16.114.26102345 or later, then reselect (UTC-06:00) Mountain Time (Alberta) as its default calendar time zone; the Mac client’s UTC−7 display indicates that it is not applying the new Alberta rule supported by Outlook on the web.

    Effective November 1, 2026, Alberta remains on permanent daylight-saving time at UTC−6. Therefore, Outlook on the web is showing the correct offset; Alberta should no longer alternate between UTC−7 and UTC−6. ^1^

    Correct Outlook for Mac

    1. In Outlook, select Outlook → About Outlook and check the build number.
    2. If it is earlier than 16.114.26102345, install the latest Microsoft 365/Outlook update. The new Canadian regional time zones are available in Outlook for Mac starting with that build.
    3. Completely quit and reopen Outlook.
    4. Go to Outlook → Settings, open the Calendar preferences, and set the default calendar time zone to: (UTC-06:00) Mountain Time (Alberta)
    5. Do not select the older Mountain Time (US & Canada) entry, because that zone continues to apply seasonal DST rules.

    Outlook for Mac uses its default Calendar-preference time zone when creating new meetings. Individual events can use another zone through the Time Zones control on the meeting or appointment window. ^2^

    Confirm Outlook on the web

    In Outlook on the web:

    1. Open Settings → Calendar → View.
    2. Scroll to Time zones.
    3. Under Display my calendar in time zone, select (UTC-06:00) Mountain Time (Alberta).
    4. Select Save.

    Update existing meetings if their times are wrong

    Changing the default fixes newly created items, but meetings already scheduled for November 1, 2026 or later may retain their previous time-zone definition:

    1. Open the affected event in Outlook for Mac.
    2. Select Edit.
    3. Select the Time zone globe.
    4. Change the event to Mountain Time (Alberta).
    5. Select Save or Send.

    Only the organizer can change a meeting containing attendees. For recurring meetings, changing the series time zone resets modified individual occurrences, so record and recreate those exceptions afterward. ^1^

    If the Mac still displays UTC−7 after updating past the required build, capture the exact Outlook build and whether only the label is wrong or meeting times are also shifted; those details distinguish a display issue from an event carrying the old time-zone rule.

    References

    1. Outlook Time Zone Changes for British Columbia, Alberta, and Manitoba ...
    2. Set the time zone for a meeting or appointment in Outlook for Mac
    AI-generated content may be incorrect. Read our transparency notes for more information.

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