This is a copy of an email I sent at work. I'm not sure I should be making noise about this here, feedback welcome.

This is your bi-yearly reminder that time is changing soon! October 25th in Europe, November 1st in North America. Less people in Canada are changing this year, with BC, Alberta, Manitoba and Northwest Territories getting rid of DST.

What's happening?

Some places in the world implement what is called Daylight saving time or DST:

https://en.wikipedia.org/wiki/Daylight_saving_time

Normally, you shouldn't have to do anything: computers automatically change time following local rules, assuming they are correctly configured, provided recent updates have been applied in the case of a recent change in said rules (because yes, this happens, and happened this year, and yes, you need to upgrade your software!).

Of course, appliances like your microwave oven will likely not change time and will need to adjusted unless they are so-called "smart", in which case they are part of the skynet botnet and should be destroyed.

If your clock is flashing "0:00" or "12:00", you have no action to take to adapt to this change, lucky you.

If you haven't changed time in six months, congratulations, your clock will be accurate again!

In any case, you should still consider DST because it might affect some of your meeting schedules, particularly if you set up a new meeting schedule in the last 6 months and forgot to consider this change.

If your location does not have DST

Properly scheduled meetings affecting multiple time zones are set in UTC time, which does not change. So if your location does not observer time changes, your (local!) meeting time will not change.

But be aware that some other folks attending your meeting might have the DST bug and their meeting times will change.

Be kind to those poor souls which might be missing meetings by a full hour because time flies backwards for them.

If you do observe DST

If you are affected by daylight savings, your local meeting times will change for UTC meetings. Normally, your meeting times are scheduled to take this into account and the new hours should be reasonable.

But now is a good time to verify that. Take a look at your schedule for the next couple of weeks and reschedule meetings before the daylight saving come up to avoid too much disruption. You have only a couple of weeks to do so right now.

When do times change, how, and and where?

As regular readers will remember, the rule of thumb is:

Spring forward, fall backwards.

That is, during the season of Spring, the clocks move forward, and during the Fall (like right now), they move backwards. That is in the northern hemisphere, but then the southern hemisphere is often saner and doesn't switch anyways.

So time will move backwards which means an extra hour of sleep. Unless you have children or bad sleep, in which case your body doesn't care about what the clock says and will wake up one hour earlier than what it should.

And of course, this doesn't happen everywhere at once, so let's see when it happens where.

Europe

The dance starts in Europe.

The change happens on the last Sunday in October at 01:00 UTC (not local time!), that is October 25th. If you are in the central European timezone, also known as Amsterdam, Berlin, or Paris time depending on your national affiliation, that essentially means that at 2:59 local the clocks will fall back to 2:00 instead of going to 3:00.

Concretely, set your watch back one hour before going to bed, go to bed at the normal time, and enjoy an extra hour of sleep or leisure.

If you have kids, you might want to start getting them to bed slightly earlier every day for a week before the change so they take time getting used to the change. If you have trouble sleeping in the morning, find your inner child and do that to yourself as well.

USA / Canada

Then it's the US[1] and Canada[2] joining the dance, on the First Sunday in November at 02:00 local (not UTC!), that is, I believe, November 1st 2025.

This means that, at 1:59, the clocks will flip to 1:00, instead of 2:00.

Concretely, do like the Europeans and tweak your clock before going to bed.

That is a little less than four weeks from now.

[1] except Arizona (except the Navajo nation), US territories, and Hawaii

[2] except Yukon, Saskatchewan, (newly) British Columbia, (newly) Alberta, (newly) Northwest Territories, (newly) Manitoba, one island in Nunavut (Southampton Island), one town in Ontario (Atikokan) and small parts of Quebec (Le Golfe-du-Saint-Laurent)

Other places with DST

This time again, I must apologize to the people of Cuba, Lebanon, Israel, Palestine, Egypt, Chile, Australia, and New Zealand, as you fine folks all have your own DST rules that are omitted here for brevity. I rely on this page from Wikipedia to be updated by time nerds accurately for this message, and it should provide you with a rough idea of what's coming:

https://en.wikipedia.org/wiki/Daylight_saving_time_by_country

In general, changes also happen in October, but either on different times or different days, except in the south hemisphere, where they might happen in September (oops, sorry NZ folks, I'm late!).

Places without DST

Everyone else, enjoy, you're on the right side of history, and we thank you for the good example you give us.

Changes since last time

There's been lots of changes since last time:

This is my interpretation of the changes announced on the tzdata mailing list here:

https://lists.iana.org/hyperkitty/list/tz-announce@iana.org/latest

If the eastward trend continues, Canada should adopt country-wide "no daylight savings" rules by 2027, although there's actually no sign of the other provinces (Ontario, Québec and so on) currently running bills to change those rules just yet. Poor Canadians like me confused about time in their countries can refer to this section of Wikipedia for details:

https://en.wikipedia.org/wiki/Daylight_saving_time_in_Canada#By_province_and_territory

... and particularly the image featured there:

https://commons.wikimedia.org/wiki/File:Canada_time_zone_map-en.svg

It also seems like the US government might finally adopt a permanent daylight saving change bill in 2026, as the "Sunshine protection act" pass the house in July:

https://en.wikipedia.org/wiki/Sunshine_Protection_Act

True to form, this was associated with absolutely ridiculous pressure from Donald Trump against republicans (his own party!) objecting to the change:

On July 14, 2026, the House passed a Sunshine Protection Act bill backed by President Trump. Nevertheless, the bill was opposed in the Senate by Republicans, including Senator Cotton. In response, on October 3, 2026, Trump shared a post on Truth Social urging Cotton to approve the bill, where he revealed Cotton's personal cellphone number and called on people to call him.

https://www.theguardian.com/us-news/2026/oct/03/trump-tom-cotton-daylight-saving-time

Given that the last time the US did a major change to the daylight savings policy (in 2005), Canada followed suit to stay in sync, it's quite possible Trump's mad dash might actually finish getting rid of DST in North America:

https://en.wikipedia.org/wiki/Energy_Policy_Act_of_2005#Change_to_daylight_saving_time

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