September 2026 - tz - lists.iana.org

Digital calendar "chaos" in western Canada
by Tim Parenti Oct. 7, 2026

Oct. 7, 2026

From CBC Calgary, 4 September 2026. Some business owners in Alberta are starting to notice disruptions and discrepancies in their digital calendar and booking apps: https://www.cbc.ca/news/canada/calgary/alberta-permanent-daylight-savings-b… One business owner said "[t]his feels like a secret Y2K that we're not ready for, I think." Those on this list will know that these discrepancies are handled in a range of application-specific ways which are often not transparent to the end-user, and that neither applications nor standards really contemplate or allow for the definition of expected behavior when zone definitions change. As such, these issues tend to crop up anytime a timekeeping change is implemented with any less notice than the typical leadtime with which folks are booking appointments. The article mentions tz's role but misstates the date of release for 2026c, which contained Alberta's change, as 7 August instead of 8 July. -- Tim Parenti

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Re: Request to Update tz Database for Manitoba Permanent Daylight Saving Time Change
by Adam Thompson Oct. 6, 2026

Oct. 6, 2026

Paul Eggert wrote: > If anyone has contacts with the Manitoba government that could help speed up that process, it'd be appreciated. Although I am employed by the Government of Manitoba, I do not have any direct contact with the Premier’s or the Lieutenant Governor’s offices. I am also anxiously awaiting the OiC to make this change official. I have heard rumours that an Order will come out sometime this week, but nothing more solid than that. However, speaking ONLY as a citizen living in Manitoba, I see a problem with Tim Parenti’s commit cd70627 to eggert/tz. While CDT and EST are the same thing mathematically, they are vastly different things linguistically, legally, socially and politically. From <theory.html>, “Use abbreviations that are in common use among English-speakers […] CST/CDT/CWT/CPT Central [North America] […]”. CDT is the abbreviation in common use here in English; I have never heard anyone refer to local Manitoba time as EST during CDT. The published material from the government so far all refers to permanent Daylight Savings Time, and the expectation is that we’ll be on CDT for the foreseeable future, not EST. If the Order in Council (which I expect) explicitly refers to “Central Daylight Time”, then “EST” might also be legally inaccurate, but we’ll have to wait and see. If the 2023 Act gets Proclaimed instead, then it’ll be a new time zone “Manitoba Standard Time”, which also does not abbreviate to EST, it will abbreviate – with the force of law – to “MBT”. We’ll all find out which route the government will take shortly, and everyone hopes they do it sooner rather than later! -Adam Adam Thompson Consultant, Infrastructure Services [MERLIN] 100 - 135 Innovation Drive Winnipeg, MB R3T 6A8 (204) 977-6824 or 1-800-430-6404 (MB only) 💻https://www.merlin.mb.ca 🤳Follow MERLIN on Social Media

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British Columbia (BC) announced PCT abbreviation for Pacific Time
by brian.laframboise＠jane.app Oct. 5, 2026

Oct. 5, 2026

Yesterday BC announced PCT as its official abbreviation for BC's Pacific Time: https://archive.news.gov.bc.ca/releases/news_releases_2024-2028/2026CITZ000… I work for a company, based in BC, that schedules appointments globally. We show time zone abbreviations in our app. We're currently concerned about the potential confusion of BC users seeing "MST" on times shown to them starting Nov 1. Specifically we're worried that a BC user will see MST and think "MST? M is mountain time. That's Alberta. Alberta is an hour ahead, so this time off by an hour" and miss an appointment. Showing PCT instead of MST could help us mitigate this issue until we can update our systems to handle this better (possibly by omitting abbreviations and showing the timezone identifier instead). That said, I am aware of the recent decision on the non-inclusion of ABT for Alberta: https://lists.iana.org/hyperkitty/list/tz@iana.org/thread/EOSYV7EGLBDW7YPKO… My questions: 1. Will IANA update the abbreviation for relevant timezones (such as America/Vancouver) from MST to PCT by Nov 1? 2. If not, can you provide guidance on when we could expect such an update, if ever? Thanks for your time.

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Fix outdated tzdata for Morocco (Africa/Casablanca) - forcing wrong UTC+1
by Younes Unknown Sept. 30, 2026

Sept. 30, 2026

Hi, WHAT NEEDS TO BE DONE: Update the system tzdata package on your infrastructure to fix the Africa/Casablanca timezone definition to standard UTC+0. WHY: Your system is currently evaluating Africa/Casablanca as UTC+1, which is wrong. Morocco's official standard time is permanent UTC+0. Because your server environment is using obsolete timezone tables, it forces a +1 hour offset on all timestamps. COMPLAINT: This is breaking production backend logic. Database queries, scheduled jobs, and client syncs are all shifting by an hour and tripping up our apps. We shouldn't have to write hacky time-offset workarounds in our code for a basic infrastructure timezone bug on your end. Please update your environment's tzdata immediately.

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[tz-announce] 2026e release of tz code and data available
by Paul Eggert via tz-announce Sept. 29, 2026

Sept. 29, 2026

The 2026e release of the tz code and data is available. This release is prompted by Manitoba’s decision to stay on permanent UTC-05, which has a practical effect starting 2026-11-01 at 02:00. Like the similar changes for Alberta, British Columbia, and the Northwest Territories in the previous three tzdata releases, there will likely be problems downstream as CLDR’s latest release cannot handle it as specified. This release contains the following changes: Briefly: Manitoba moves to permanent -05 on 2026-10-31. Changes to future timestamps Manitoba’s 2026-03-08 spring forward was its last foreseeable clock change, as it moved to permanent -05 thereafter. Model this with its traditional abbreviation EST. Although the change to permanent -05 legally takes place on 2026-10-31, temporarily model the change to occur on 2026-11-01 at 02:00 for the same reason as other recent temporary hacks. (Caution: see “NOTE FOR 2026b TEMPORARY HACK FOR CLDR AND CANADA” below.) As the change affects both America/Winnipeg and its backward compatibility link, the obsolescent setting TZ="Canada/Central" will now use the abbreviation EST for affected timestamps, akin to TZ="Canada/Pacific" behavior introduced in 2026b. Another TZDB release may be needed soon if any of the portions of northwestern Ontario historically aligned with America/Winnipeg do not follow. For now, given the short leadtime with Manitoba’s announcement, assume that they will, to avoid creating new zones that may not be needed if no divergence occurs. NOTE FOR 2026b TEMPORARY HACK FOR CLDR AND CANADA: This temporary hack works around a Canadian timekeeping bug in Unicode CLDR 48 and earlier. Unfortunately it also causes zic 2023d through 2026a, in the default slim mode, to generate a TZif file that does not conform to Internet RFC 9636 §3.3. The buggy file in turn causes some TZif readers, including tzcode itself, to ignore America/Vancouver’s 2026-11-01 02:00 transition from PDT (tm_isdst=1) to MST (tm_isdst=0). Although the buggy file does not cause any known TZif reader to mishandle UT offsets, caution is advised when using zic 2023d through 2026a to compile data from more-recent tz releases. To work around this problem when using these older zic versions, use ‘zic -b fat’. Changes to past timestamps In 1925 Ireland fell back on 09-20 not 10-04 (thanks to Stan Ulbrych). Changes to commentary Discussion on timekeeping practices in northwestern Ontario has been expanded in light of Manitoba’s recent announcement. It is not yet known whether or to what extent these areas may adapt their own timekeeping practices in response. Here are links to the release files: https://www.iana.org/time-zones/repository/releases/tzcode2026e.tar.gz https://www.iana.org/time-zones/repository/releases/tzdata2026e.tar.gz https://www.iana.org/time-zones/repository/releases/tzdb-2026e.tar.lz The following convenience links are also available, although they may point to the previous release until the relevant caches are refreshed: https://www.iana.org/time-zones/repository/tzcode-latest.tar.gz https://www.iana.org/time-zones/repository/tzdata-latest.tar.gz https://www.iana.org/time-zones/repository/tzdb-latest.tar.lz Links are also available via plain HTTP, and via FTP from ftp://ftp.iana.org/tz/releases with the same basenames as above. Each release file has a GPG signature, which can be retrieved by appending ".asc" to the above URLs. Copies of these signatures are appended to this message. This release corresponds to commit 039ef27cc5f062a2055cb67435d6d71adbefd27d dated 2026-09-29 17:14:38 -0700 and tagged '2026e' in the development GitHub repository at <https://github.com/eggert/tz>. Here are the SHA-512 checksums for the release files: 623af2d5c611ce5d9f6d07ceeb09721db03ed90e8e74e027f96fc402eb948fc8a7e9aecac2611e41fb501bdc2592a78020375ad677d887beaacb2fd5da9b9815 tzcode2026e.tar.gz 5be2f875f73b75e5783c474bf7a6c768e433cc90283f8fc6a75e3d05bd92aec97936e8a55ccca5e880b5dacc18ba65932bab0e783e1ed5d2af4a3a4df95512be tzdata2026e.tar.gz 757be14e5e01eaeaa995ead6948456772d6b451ca0ce254de40a2167bf7c480ab03de61e19e62c2cfe8bb5ade7f5c938fd6ab70d4cc41ae6d867333076963996 tzdb-2026e.tar.lz Here are GPG digital signatures for the release files: -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmq8VQsACgkQ7ZfpDmKq fjSKDg/+L/XjXhCZLKRzilGujnZtImSeEKbXvBPWCrB/FkjYx1SG9LTP3dgc1dbt qA3IO3hRWiI3rWXPs5kMzl9kQIZt8SOpHl15Sy+xOoAn2gbJk1EQkwf3gvPuoTce tGBvHdWLI7pV/81YUn339S3vsbLZPC896dHKEz2YCmmOqF2ExVykNMQKiwy6RhEv KiMfbkgAufYATwOXY2+F7s9dpmO5CihEYRhgPA9GDlaoLXL03yywg1Zq7zbH2l5N BKoCmVswEcQCF4qMY39MSj0hHAIr+C4BYsEWWg24mfJ2ECBGErDlEB14PQLmBiuO HTBgCOdrN8NaQWted8+Gru0K32liMTI3KzTNC0BvEmIK7/ChEO5cxwpmQzrgVgyI FIpdCfTJB2Q4VSdm2JWOpwr6fY6yEJbVt2VgbEEi3o8T6H9tW8/7EQDPJRgbVt0G Gieejx1LbJl90AaLFJ7ARICioyAKRgUDZYayaYcUsOZkSXbbmPONzPyaM84CxKO9 S1xWVW506dhDZ6ydlCq0Zy8+7VDmo4wtI4lXeqan+pVL8stgG3x9yZvGlvBkbfcf eUNWd9uFttEaHuP164pA3I3+hNpebAolIJfsNHBHB5DFZJ+AZ16s8BUdLZiQgcge mdtdT03Cn/HrgaEaiYnPTNtOFKfY43KxrXMGEqe8RPHhjey1LDw= =k+Db -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmq8VQsACgkQ7ZfpDmKq fjQSFw/9Ft+BbeEzD6Sfdxuab5WsA48lSxHPwroL01fJI7+qRTqbCXdnjXKbWglT iIvuTSD93Dtsl81cx9y+wDFe3XTYdlCUmTX+kP4wTNwQ6ypkWZmB2YWVACdmXeec g8S6ZkZXnhOE9qAJ/5DVleOHqBb8ozQavqtk7mve4e1vEXLTW9ul2Szn4dKmHoaU EYDo2eSsiEop6z5fhnA2qUYH2dCfKIahLv1yyXG4NmMUFyDVYH0YOPdREP9cxpWt cFoUAktuO2JaQwh2DrU5a+jpPJqasH8Puy2wmZnQNzHtFw/vCiXTBdT+erYjOnFB bOfgwFVMU/a89Zp44ctdVhkXDIRw8prZKpl2Fgc3e/KUPbRJwteuI9AVKQUKQhPN mVR9O8ABVwT8C2QI1sTo8R5zfmYgNaHNxDEEJm/guxmylBJ2jqsC0p7YtiFUfVWU 5N1Wg/nvsm80Jvi9s5748P+NKlJaBYJuVffSsqKmzIE+6G8uMXAfQeM8QKGa314l c3KQ6eWeVJLKmJp7yAnX/EneihQ8JhG8r98Z03+2MiT2uetQYZRhLKOPFWZRt9VJ v6qm3bQE7Phx/o9Mi5wueAd3yDIEPvMlgJmeOGno5QtbPJQoHmo68TLbwfC745Od qxqS8c5v5HLrY7dqafHpojrbL7/Q8dKi4TxP1exyO0FwKJxlJRg= =fybA -----END PGP SIGNATURE----- -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEfjeSqdis99YzvBWI7ZfpDmKqfjQFAmq8VQwACgkQ7ZfpDmKq fjRuBRAAiLyW7PTQiSKF2S503Yo1thkAwdENV8CG65Q5T2J1aedYxceeVZiyQFqU QyVHB4fKw+2nJQCf7fqmljiMdqT9WtBZipyGY+nmTqFeJnghYv5p/uywtCRQX6rs rSmb/mQDgh8V7ndDW5K/OiO3i8ux81xkry/zrlTGj5W37UhqDQVo5/cQjHodwqm2 /ZHtfS3tbHQ2O9gHMPeDXVrd1/gU/kA8LH2HU8JXLpkWJNcoiTi6x+8l9yl2FLFx htih6V9P09LQSGV/wdhrDrZB6DhXw71ixTGP3uYdOAHPHH91x3wwChO9LkIDRdeK CwoGfSkuhdMvFO8Ss4GMuBr1xtinZ17wkjQMWaVb41mrqFWwiPTOjXw6iZ4DQzhx CBziTsZqkErw9fSC287kpfPojzs4CSDlI+AePLqOsp3CflYLZ6A+YvqEhzz+eU+0 EHyRHSKUjChoE6RhjbbsKVNu9i/DjGrKltLl5Q33UsxDNKtx1oQUDW+rZZtKC7Zu APF0haFQVt3uaCe6se6KV48A2+BtC/CzY6PjfPTL7JSJFjScxd96TFQ/7w7J+uNu 95JhToWMmYykvX9pCXqrXhmdOBHpZpKoZjInQollcDWedpKhKZGX4CDn7MYfLf7+ UMUaFMJ+S2ahV/W16sIVFQ1jhxpizhjKcRGK+bdX7iE7gb8x/Ao= =03Tp -----END PGP SIGNATURE-----

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Re: [EXTERNAL] Re: Request to Update tz Database for Manitoba Permanent Daylight Saving Time Change
by Paul Eggert Sept. 29, 2026

Sept. 29, 2026

On 2026-09-25 13:12, Ashish Kumar wrote: > https://www.youtube.com/live/-7QOJOkAn5g?si=A1aNLnd8qHUZm09-&t=427 proclamation has been signed and hopefully published soon on thehttps://web2.gov.mb.ca/laws/statutes/index_procs.php Thanks for the heads-up. That video of the proclamation signing doesn't say when the proclamation takes effect, a detail that will affect exactly what goes into TZDB, but presumably that detail will be published soon at <https://web2.gov.mb.ca/laws/statutes/index_procs.php>.

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Timezone update required for Africa/Casablanca: Morocco permanently switched to GMT+0
by Hafid Idoukharaz Sept. 29, 2026

Sept. 29, 2026

Dear tz database team, I am writing to report an outdated timezone rule for Africa/Casablanca affecting applications like Firefox that rely on internal IANA/ICU timezone data. Morocco has officially and permanently returned to standard time (GMT+0) as of September 20, 2026. However, because the current timezone database still associates Africa/Casablanca with GMT+1, browsers and software using this outdated rule continue to apply a +1-hour offset incorrectly. Could you please update the tz database rules for Africa/Casablanca to reflect permanent GMT+0 status as of September 20, 2026? Thank you for your time and hard work in maintaining the time zone database. Best regards,

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Re: Request to Update tz Database for Manitoba Permanent Daylight Saving Time Change
by Lucas, Michael Sept. 28, 2026

Sept. 28, 2026

FYI, my company was looking into this as well as the sooner we get IANA updated the better. We heard the following: "From the Premiers Chief of Staff, the official word is it's a proclamation and the order in council will be out this week" Thanks michael lucas | Senior Software Developer | Canada Life The contents of this communication, including any attachment(s), are confidential and may be privileged. If you are not the intended recipient (or are not receiving this communication on behalf of the intended recipient), please notify the sender immediately and delete or destroy this communication without reading it, and without making, forwarding, or retaining any copy or record of it or its contents. Thank you. Note: We have taken precautions against viruses, but take no responsibility for loss or damage caused by any virus present.

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Manitoba adopts year-round UTC−5, will not fall back in Nov 2026
by Tim Parenti Sept. 28, 2026

Sept. 28, 2026

Manitoba's long public engagement survey on DST, which ran from late-May through the end of August, has concluded. At the time it started, I had expressed some hope that the long engagement period would mean that they would not be rushing into any changes before 2027: https://lists.iana.org/hyperkitty/list/tz@iana.org/message/QSABAZELHHCDDTOF… Well now the results are in… and reports are that the province will NOT be forming the "Prairie time zone" that Premier Wab Kinew had publicly opined about, and will instead be adopting year-round UTC−5 on just about 6 weeks' notice: https://news.gov.mb.ca/news/?item=75397 https://www.cbc.ca/news/canada/manitoba/daylight-time-manitoba-9.7347844 From the government release: "A total of 92 per cent of Manitobans surveyed wanted to see an end to seasonal time changes. A majority of Manitobans (58 per cent) preferred to stay on permanent DST, while 34 per cent voted to eliminate the time change but stay on standard time." While other options may have required legislative action, it appears the *Official Time Amendment Act*, assented to 30 May 2023, allows for this, but I am still seeking confirmation on whether that is indeed the mechanism that will be used. This just broke a few hours ago (around 09:20 UTC−5), but obviously we will need a new tz release quite soon to reflect this. America/Panama is the main workaround on year-round UTC−5 in the interim until the necessary changes to America/Winnipeg propagate downstream. -- Tim Parenti

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Request to Update IANA Time Zone Database for Manitoba Permanent Daylight Saving Time
by Mostafa, Ahmed Sept. 28, 2026

Sept. 28, 2026

Hi, I am writing on behalf of the Government of Manitoba to advise you of a recently announced change to Manitoba's time observance and to request that the change be reflected in the IANA Time Zone Database. On September 17, 2026, Manitoba Premier Wab Kinew announced that Manitoba will move to permanent Daylight Saving Time (DST) and will no longer observe the seasonal clock changes. According to the announcement, clocks in Manitoba will not revert to standard time on November 1, 2026, and the province intends to remain on DST year-round. [news.gov.mb.ca]<https://news.gov.mb.ca/news/?archive=&item=75397> Official Manitoba Government News Release: Manitoba Will Move to Permanent Daylight Saving Time<https://news.gov.mb.ca/news/?archive=&item=75397> Premier's Announcement: Premier Wab Kinew Announces Manitoba Will Move to Permanent Daylight Saving Time<https://news.gov.mb.ca/news/?archive=&item=75397> We would appreciate your help to facilitate inclusion of this change in the IANA Time Zone Database. Please let me know if any additional information is needed. Best Regards, Ahmed Mostafa Executive Director, Enterprise Architecture Office Digital and Technology Solutions Department of Innovation and New Technology Ahmed.Mostafa(a)gov.mb.ca<mailto:Ahmed.Mostafa@gov.mb.ca> / Cell : (204)-914-4790 1100-215 Garry Street - Winnipeg, MB

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