Microsoft's Canada timezone troubles leave admins fixing calendars
theregister.com
theregister.com
September 22 for Manitoba https://github.com/eggert/tz/commit/cd706278466a3ad431f0ad39...
July 8 for Alberta: https://github.com/eggert/tz/commit/ddcb5fa20791c3c5f1a15194...
April 22 for British Columbia: https://github.com/eggert/tz/commit/8b46071fd85a7a9434d63894...
Microsoft doesn't use tzdata
Even if you update your Windows settings to say the new correct time zone, it still doesn't go back and update the time zone that future Outlook meetings are scheduled for.
I noticed that my personal calendar on my phone seemed fine, and iOS seems to book meetings based on a TZ identifier (America/Edmonton) rather than offset or a name like 'Mountain Time.' That system seems to have worked well in this case.
It's tricky, do you want future meetings to follow the city they're in, or do you want past meetings to properly track when they happened across zone redefinition (and what even is correct)? There's no simple way to get this right everywhere.
I still think the path Outlook took wasn't ideal for the majority of their customers in the effected places though.
I thought using the city (America/Edmonton or America/Vancouver) does both of these though?
The Albertan could have set the time to 12:00 in Europe/London, but probably few people do this unless they're expecting to travel to the other place.
1. the London person owns it, schedules in local (London) time 12:00
2. the London person owns it, schedules mental math explicit Alberta time 05:00
3. the Alberta person owns it, schedules in local (Alberta) mental math time 05:00
4. the Alberta person owns it, schedules in explicit London time 12:00
You cannot get all of these working by software only no matter what you do, because there "mental math" time cannot take into account the implicit expectations, 1 and 4 will be correct as stated (the meeting is at 12 London time) but 2 and 3 what do you do? How would you differentiate between "mental math what I thought Alberta time was" vs "I really meant it at this Alberta time"
Consider a Doctor's appointment for Dec 20, 2026 2pm in Calgary. Regardless of whether its booked a year ahead (ie before the new time zone rules were decided) or a week ahead (after the rules were decided, and consequently a different UTC time), the expectation is that it will be at at 2pm local time.
Just in BC there were multiple changes, some of which (eg Eastern Kootenays) were decided much more recently than 7 months ago. The MSTNO area didn't change, but in not changing its offset relative to the rest of the province did.
Displaying historical data, ranges that include the moment that the new definitions come into effect, temporal and/or spatial aggregations that span multiple timezone definitions... lots of tricky things can pop up.
That's not to excuse Microsoft. This isn't the first timezone change that has happened, and they should have the most robust change management process in the world for stuff like this.
That said, operating systems need to get the correct files in place.
Edit here's the TZ Announce list. Note that Cuba's very recent decision not to leave DST is included.
A) you need the new timezone definition available and pushed everywhere regardless. It doesn't matter what zone the RTC uses.
B) For future events, you need a way to manage what happens when the time zone they're scheduled in changes OR when they change to a new time zone. Microsoft has been terrible at this part on every time zone change I've been aware of (it's hard, but it's not this hard, and the Canadian change was published with sufficient notice, and time zone changes happen for recurring events, this is not a new requirement). But there's no connection to the time zone of the RTC here either.
If you have issues with poor behavior specifically around transitions, that could be related... Repeatedly moving forward or backward for DST is something where keeping the RTC in UTC would help.
Last time I looked best practice for a real calendar app was to store in local time with time zone, not UTC with offset.
UTC is time in theory. Points in time separated by numbers of seconds. Great until the reality of time being a social construct breaks your assumptions. Still, use UTC until you are actually building a calendar app. Depending on your use case, consider storing timezone instead of offset.
best practice for a real calendar app was to store in local time with time zone, not UTC with offsetThe "time" at which future events are scheduled by humans (i.e. not the time when future events are predicted, like astronomical events), is not a "time", but it is a different data type, which must have a different name and which must store different information (i.e. legal date and time at a certain location).
For future events, the "time" when they will occur is not "time", but a different data type, which should be called "legal time", "local time" or the like.
The "local time" for future events must include the geographic location attached to the event, from which the applicable time zone can be derived, at a time close to when the event is due.
For future events, you have to store them as location + timezone-naive dates and times, a.k.a. local time. Since if a meeting at a certain location is scheduled at 9:00, which is currently at 02:00 UTC, and then a timezone change happens, and UTC 2 suddenly means 10:00 at that same future date and location, the meeting will still happen at 9:00 local time. You cannot store future events as UTC only.
No idea what Microsoft is doing.
Our IT department ran a couple scripts last week and everything this week has been smooth sailing.
Things I have run into problems with have been my smart thermostat (ecobee, now fixed), my Philips Hue lights (most of my automations are via Home Assistant, but I have a handful that rely on colour temp in the Hue app), and my Ford car. (Auto time zone and auto time aren't separately configurable, and auto time zone puts me in the wrong time zone.)
BC: March 2 Alberta: April 20 Manitoba: Sep 17 Western Ontario: Oct 13
Manitoba didn't give much advance warning. Western Ontario is on the same time zone as Manitoba so it was very confusing there until at the last second it was clarified. So Microsoft has an excuse for screwing up Kenora. Vancouver though should not have been a problem.
it took around 40hrs for my apple watch and my iPhone to start agreeing on what time it was.
This is what happens when a part of country does not follow. China is the other extreme. They got one stupid timezone, so one part of the country is dark AF, but then other side is daylight.
This all comes down to whoever is running the government.
US should also abolish stupid daylight savings, but northern politicians do not want while there is bipartisan agreement to make the savings time permenant.
- Regional time zones? Stupid.
- One time zone for the entire nation? Stupid.
- Daylight Savings Time? Stupid.
- When Western Canada gets rid of DST? You guessed it... stupid!
Everything is stupid!
Did i say everythign is stupid? No. I only showed the part of the issues.
You went down the slippery slope went extreme.
That bipartisan agreement will evaporate after the first winter on permanent DST and either DST will come back or we'll switch to permanent standard time. That's what usually happens when people try permanent DST.