No leap second will be introduced at the end of December 2026

https://datacenter.iers.org/data/latestVersion/bulletinC.txt

311 243 13 days ago

datacenter.iers.org

Wingy• 13 days ago

Does this mean the negative leap second isn't happening anymore?

linux2647• 13 days ago

Not anymore forever. We’re just not adding one for this year. We might need one next year, we might not. It all depends on the Earth’s rotation and orbit

NooneAtAll32• 13 days ago

and Earth's rotation was too fast for last several years

we were all waiting for the negative leap second to finally happen - but cowards got too afraid

tedd4u• 13 days ago

There's an opportunity to insert or remove a leap second twice a year. They only decide about 6 months in advance of each opportunity what to do (leap second, skipped second, or do nothing).

voidUpdate• 13 days ago

I enjoy how Chrome asks me if I want to auto translate from German to English. Where did it get German from? It's French!

simlevesque• 13 days ago

It's a mix of french and english... so it's german.

lopis• 13 days ago

A mix of English and French is just called... English

bhaney• 13 days ago

Probably from the "Content-Language: de" header

raverbashing2• 13 days ago

Ok but that makes even less sense

rpozarickij• 13 days ago

According to Wikipedia [0] the headquarters of IERS (International Earth Rotation and Reference Systems Service) is in Frankfurt, Germany (contact information on their website [1] has an address in Frankfurt too). The web server hosting the linked file also contains German text in its error page:

Dieser URL wird nicht beantwortet. Bitte wenden Sie sich mit Ihrer Anfrage an das Bundesamt fuer Kartographie und Geodaesie.

[0] https://en.wikipedia.org/wiki/International_Earth_Rotation_a...

[1] https://www.iers.org

bombcar2• 13 days ago

"To authorities responsible for the measurement and distribution of time" is just the best preamble ever.

flexagoon• 13 days ago

The only better thing is the organization being called "International Earth Rotation Service"

nullorempty• 13 days ago

Oh boy :) I think that would come with IERS Tax.

layer84• 13 days ago

Someone should establish the Interplanetary Sun Orbiting Service.

steve1977• 13 days ago

Sounds like something out of a Douglas Adams novel.

tetris11• 13 days ago

Or XKCD. I love patch day.

bombcar2• 13 days ago

It’d fit right into Thief of Time by Pratchett - the monks literally measure and distribute time.

srdjanr• 13 days ago

They should call themselves Time Lords

dotwaffle• 13 days ago

Traditionally, that was the email address for the NTP service at various organisations, in the same way that postmaster was for the mail service.

ninju3• 13 days ago

For those who need more context of who the Time Lords are

The Time Lords are a fictional ancient race of extraterrestrial people in the British science fiction television series Doctor Who. In-universe, they hail from the planet Gallifrey and are stated to have invented time travel technology.

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

declan_roberts• 13 days ago

"Director Earth Orientation Center of IERS Observatoire de Paris, France"

Even the titles are sci-fi.

404mm• 13 days ago

“Time Lord” could have been used instead of Director. At least once. Please.

CommieBobDole• 13 days ago

For many years, the title of the leadership role over the various precise time products at the USNO was "Director of the Directorate of Time"

MengerSponge• 13 days ago

Do they have an insignia or patch? Can we buy it?

danbruc• 13 days ago

Planetary Defense Officer [1]

[1] https://en.wikipedia.org/wiki/Planetary_Defense_Coordination...

srean• 13 days ago

What happens to systems such as Spanner under these circumstances?

Is it a headache or a non-issue

metalliqaz• 13 days ago

Leap seconds are not added on a regular schedule like leap days, they depend on physical measurements of Earth. So high reliability systems with comprehensive timekeeping would not be perturbed by these choices, I would think.

bri3d• 13 days ago

It’s a huge problem. The most common approach to address it is called smearing; the duration of each second for a 24 hour period ahead of the “leap” is adjusted. For strict ordering systems this works as each device maintains time sync with the global clock, the duration of a clock cycle is just slightly different. I think this was in the original Spanner paper, actually.

Some rare systems use monotonic oscillator seconds and ignore the earth rotation second, but if you ever have to translate those to real time, you get an accumulating disaster over time and it’s generally regarded as not a good idea.

criddell• 13 days ago

I wonder if that's what electricity producers do? If you are selling 50 or 60 Hz service, an extra second here or there must really mess things up.

ChrisArchitect• 13 days ago

Notice they only said leap second.

Meanwhile....

International timekeepers to vote on changing the leap second to a leap hour

https://www.scientificamerican.com/article/international-tim... (https://archive.ph/GnQUj https://news.ycombinator.com/item?id=48842329)

_joel• 13 days ago

really, my I just don't have the time to keep up with this.

icepush• 13 days ago

We can change that!

tialaramex13• 13 days ago

A leap hour wouldn't affect you.

In practice it will never affect anyone because it's a legal fiction, but even if you pretend to believe we would actually introduce this "leap hour" it would be in the distant future long after we're all dead and if there are still humans who have any idea the year 2026 happened they're not sure which of Donald Trump, Taylor Swift, Tony Stark and John McClane were real people.

Edited to add:

This is such a ridiculously long time frame that they might not be sure whether we were worried about climate change, for them that's either a disaster they survived (and maybe most didn't) or it's a weird blip in their historical charts which they struggle to explain. Did our civilisation do something very, very stupid? There is a flammable gas deep underground, did we set fire to it because we were crazy? Why the hell would we have done that? There are signs we deliberately set fire to the coal which is a toxic rock also found underground? That would explain the global climate going nuts. Maybe it was a ritual or something. Ancient people are mad.

delichon2• 13 days ago

Hear me out. We can just mount jet engines along the equator and rotate them 180 to gain or lose time. And then connect them to my snooze button.

gumby• 13 days ago

The problem is future societies harvesting the engines for interstellar probes. This problem has been discussed in a series of books by Larry Niven.

tenthirtyam• 13 days ago

There's a graphic novel by Cixin Liu "The Wandering Earth" where they not only stop Earth's rotation with this method, but also propel Earth out of the solar system (for what appear to be good reasons, I might add). Can't quite remember what fuel they used for the engines.

flippyhead• 13 days ago

I feel like we can all just jump at the same time. I mean, we only need a second or two, right?

ninju3• 13 days ago

Well...we would all have to be at the same spot so that we don't cancel each other out. But that would come with its own challenges

https://what-if.xkcd.com/8/

(oh and it wouldn't be strong enough to affect the Earth's rotation)

slashdave• 13 days ago

Maybe a whole bunch of people can charter some planes, fill them with weight, and just travel full around the earth to where they started.

dylan604• 13 days ago

Wouldn't it just be easier to have Superman fly around the planet a bunch of times really fast to do the same thing? Then you wouldn't have to worry about having to deal with all of that engine maintenance.

fragmede• 13 days ago

Superman is best used elsewhere. https://www.smbc-comics.com/comic/2011-07-13

Polizeiposaune• 13 days ago

It would appear that this has worked as they haven't had to insert leap seconds for quite a while.

Perz1val2• 13 days ago

No, jet engines push against the atmosphere and the atmosphere is a part of the earth

delichon2• 13 days ago

https://physics.stackexchange.com/questions/608372/if-a-jet-...

It would have to be rockets. My napkin says 2B starship boosters and 250K tons of propellant per second should give us around 1 second per year.

Sohcahtoa82• 13 days ago

If the jet engines are pushing hard enough, then the atmosphere won't be a part of the earth for long.

rzzzt2• 13 days ago

Then we'll have to decrease the radius a bit.

s0rce• 13 days ago

You could actually move very large quantities of water around and probably have a measurable impact. Like draining the California central valley aquifer.

nofunsir• 13 days ago

The Three Gorges Dam has already given us 22 more microseconds in the year. Basically, the Chinese have converted the angular momentum of every molecule on Earth, including you... into electricity.

returningfory22• 13 days ago

As one HN comment said years ago: I feel leap seconds have always lived in the wrong abstraction layer.

They should live in the same abstraction layer that does leap days and daylight savings: the time zones.

thwarted• 13 days ago

Leap days, February 29th, are not at the level of time zones. Different time zones do not disagree as to when March 1st will occurs immediately after February 28th.

RugnirViking• 13 days ago

god that would be awful. Can you imagine time zones being one second off from each other. Or two or three? ah yes, india is GMT+4:30:03, where europe is GMT+0:59:58

TimTheTinker• 13 days ago

The TZDB could handle it though

muvlon• 13 days ago

Already a thing between UTC and TAI.

stvltvs• 13 days ago

The changes in Earth's rotational speed that leap seconds help account for affect the whole globe. Why shouldn't the effects be noted in the global time standard?

returningfory22• 13 days ago

Same with leap days though?

The point is that it's weird that we handle a day every 4 years off in a different way to a couple of second being off.

layer84• 13 days ago

That would create much more chaos, because every region autonomously decides on its timezone(s). You'd have different countries and/or timezones using different leap second counts.

clickety_clack• 13 days ago

Yes! I yearn for the day when central daylight savings time is 1:00:00:36 behind eastern time, but standard central time remains offset by 1 hour exactly (except for leap years, which are obviously 1:00:00:36 offset all year round).

t1234s• 13 days ago

They should have a global holiday to celebrate the people who maintain time/date related code in OS kernels that keeps the world from imploding.

radomir_cernoch• 13 days ago

Lol. Exactly!

ortusdux2• 13 days ago

I like the argument that we should have 12 months that are exactly 30 days long, and then merge whatever is left into a single timeless holiday.

tialaramex13• 13 days ago

BurningFrog• 13 days ago

There would be 5-6 days without time every years?

soiltype• 13 days ago

I've often dreamed of and revisited this idea. I first started thinking of it seriously when I realized I was paying the same rent in February as in January despite a significantly shorter-than-mean (30.4375) month...!

My ideal year is 12 months, each 5 weeks long, each week 6 days long. At the summer solstice, 3 intercalary days (bank holidays), at the winter solstice, 2 or 3 intercalary days depending on leap year.

suspiciousape• 13 days ago

I thought it was 13 months exactly 4 weeks long, which takes us to exactly 364 days

raverbashing2• 13 days ago

Lol the Kernel is "easy" it's userspace and distributed systems that are a b*tch

mtoner232• 13 days ago

They're cool people but like it doesn't stop the world from imploding. Most of all of our code is full of trivial bugs and edge cases and most people don't mind too much. Certainly no one cares about leap seconds, they hardly even notice DST or leap days

exegete• 13 days ago

The difference between Coordinated Universal Time UTC and the International Atomic Time TAI is :
from 2017 January 1, 0h UTC, until further notice : UTC-TAI = -37s

This means the atomic clock is behind the solar clock by 37 seconds? I also don’t understand the reference to 2017.

doctoboggan3• 13 days ago

I also don’t understand the reference to 2017.

My guess is that is when they last changed the offset, so the -37s has been in effect since then.

flohofwoe2• 13 days ago

Apparently December 2016 was the last time a leap second was inserted, at least that's what Wikipedia says:

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

NooneAtAll32• 13 days ago

we were ought to insert a negative leap second, but cowards got too afraid it would break code

pdonis7• 13 days ago

This means the atomic clock is behind the solar clock by 37 seconds?

If anything, it's the other way around.

A UTC day is defined as exactly 86400 SI seconds. But an actual mean solar day is a few milliseconds longer (although the difference is not constant due to irregularities in the Earth's rotation--but the average difference is expected to slowly increase over time). SI seconds are counted by atomic clocks, so UTC advances its day by one every 86400 atomic clock seconds.

But a solar clock that advances its day by one every time the mean sun reaches noon (it has to be the mean sun because the rate at which the actual sun moves across the sky varies over the course of a year, we need to look at the average) will advance its day a few milliseconds later than UTC does. Or, to put it another way, each time period that the solar clock says is exactly 86400 seconds, is a few milliseconds longer according to the atomic clock.

As this happens day after day, the difference accumulates, and when it gets close to being a full second, a leap second gets inserted into UTC, so that one of its days is 86401 seconds long instead of 86400. The reason for this is that UTC is not just counting atomic clock time; it also has to stay in sync with where the sun is in the sky since so many human activities are tied to that. And we humans have defined "in sync with the sun" to be "within a second of the average sun". In other words, we want UTC noon to be within a second of mean solar noon on the prime meridian.

So the 37 seconds is how far mean solar noon would be behind UTC noon, if we didn't use leap seconds--at UTC noon, the mean sun would be 37 seconds short of actually crossing the prime meridian in the sky.

Vvector2• 13 days ago

"In other words, we want UTC noon to be within a second of mean solar noon on the prime meridian."

Why?

If I travel 1 mile east or west of the prime meridian, my solar noon now comes 2-3 seconds earlier/later. It's nearly impossible to have your local time match your local solar noon. For most of the population, solar noon is, on average, 30 minutes off of 12:00 noon.

Plus, solar noon varies from day to day by 10-20 seconds. Check the charts out. https://www.timeanddate.com/sun/usa/new-york

doctoboggan3• 13 days ago

What causes the unpredictability in this? I would have guessed we have earth's rotation and orbit down to many decimals. Does geological activity, weather, or something else cause rotation speed differences that we just can't predict?

flohofwoe2• 13 days ago

Since I was checking the Wikipedia article anyway (for when the last leap second was inserted), it also has an answer for this:

"Because the Earth's rotational speed varies in response to climatic and geological events, UTC leap seconds are irregularly spaced and not precisely predictable."

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

moi2388• 13 days ago

Yes. Geological activity, movement in the outer core, atmosphere, oceanic currents, melting ice, earthquakes, to name a few.

Earths rotation has been unusually fast lately. So there is not enough drift to warrant a leap second.

entrope• 13 days ago

Yes, all of those and more. Our measurement precision is much better than the year-to-year first and second derivatives of day length. https://datacenter.iers.org/singlePlot.php?plotname=Bulletin... has the most relevant plot to this; the vertical jumps reflect leap seconds. (IERS has other plots for other dimensions of rotation, but I like this one.)

doctoboggan3• 13 days ago

Very interesting, I wonder what happened in 2020 that causes the rotational speed to start drifting the other way?

Pandemic -> more people working from home -> less people in tall office buildings -> faster rotation (like a skater pulling in their arms).

Probably not remotely true but it would be funny.

_alternator_3• 13 days ago

In short, yes, the weather, geology, and signicantly, human movement of water via aquifer draining and dam building, as well as glaicial and ice melts, all contribute to unpredictable changes in the earths rotational period, as well as the axis of rotation. The models for this are IIRC trigonometric polynomials of fairly low order, so even if we could model the unpredictability perfectly, truncation error would limit our ability to distribute the model at super high accuracy. The existing models are built in to, eg, satellites, so you can't just make them arbitrarily complex.

Fun fact: leap seconds will stop being a thing soonish. I think they phase out in 2035, with a delay because Russia needed time to update glonass satellites.

(Note: on mobile, this is from memory, details need checking ;))

thewebguyd• 13 days ago

as well as the axis of rotation

A frightening fact, the 2011 magnitude 9.0 Tohoku Earthquake shifted the position of the Earth's figure axis about 17 centimeters, making days about 1.8 microseconds shorter.

tialaramex13• 13 days ago

2035 is the agreed drop dead date.

Everybody agreed that "Leap seconds" are a sufficiently bad idea that they should be replaced by 2035. Nobody has agreed how to fix it, and "Just turn them off" isn't technically legal. However, "What if there were Leap hours instead?" is technically legal and of course those hours would happen in the very distant future (likely after our civilisation is gone) so it's functionally identical to "Just turn them off" but without legal problems.

Now, I'm English, and England loves this sort of hack. You may have heard that controversial UK politician Nigel Farage "resigned" as a Westminster MP recently and that's not technically true because you can't resign, historically people hated that job and so you can't resign and we never changed that, but what you can do, and everybody does, is get assigned an "Office of profit" in which legally the King is paying you, an MP can't work for the King so you can't be an MP any more. The "Offices of profit" in question aren't real jobs† and don't pay real money, like this "Leap Hour" they'd be a legal fiction. So everybody says you "resigned" but in fact you legally can't do that...

† I mean, historically they were real jobs that made sense which is why the King paid somebody to do them, but England is very, very old so they haven't made sense for centuries and serve only as a legal fiction today.

lloeki• 13 days ago

Russia needed time to update glassnoss satellites

GLONASS maybe? or really glasnost era satellites?

Xenoamorphous• 13 days ago

A butterfly flaps its wings in Tokyo and we lose a leap second.

N19PEDL2• 13 days ago

because Russia needed time to update glonass satellites.

Why is this? As leap seconds don’t occur on a regular frequency, I assume they are not hardcoded on the software or hardware on board, but the control centre uploads them on the satellites enough in advance once they have been scheduled. So why can’t the control centre just stop sending those updates?

jvanderbot• 13 days ago

I prefer ephemeris time

Dylan168077• 13 days ago

The models for this are IIRC trigonometric polynomials of fairly low order, so even if we could model the unpredictability perfectly, truncation error would limit our ability to distribute the model at super high accuracy. The existing models are built in to, eg, satellites, so you can't just make them arbitrarily complex.

What are the satellites doing with the models? They're not deciding leap seconds on their own, I hope. So I don't see why the leap second decision would be locked to low accuracy.

Also I would expect doubling the precision to give you a 3-4x slowdown on the math or adding orders to have less effect, and the amount of available computation spent on those models to be like a tenth of a percent at most, so the extra cycles wouldn't be an issue. What am I missing here?

To me it seems like unpredictability is the only real issue.

bloppe• 12 days ago

Phasing out leap seconds is such a crack pot idea. Read the resolution [1]. The conclusion hinges entirely on accepting the immutability of these 2 premises:

  recalling that the CGPM at its 26th meeting (2018)
    - stated that UTC is the only recommended time scale for international reference and the basis of civil time in most countries,
    - recommended all relevant unions and organizations to work together to develop a common understanding on the realization and dissemination of reference time scales with a view to considering the present limitation on the maximum magnitude of UT1 - UTC to meet the needs of the current and future user communities,

I accept all the other premises from the resolution, but then the obvious conclusion should be to just recommend TAI instead of UTC for any application that could be disrupted by leap seconds, instead of butchering UTC and turning it into just a worse version of TAI.

[1] https://www.bipm.org/en/cgpm-2022/resolution-4

ahazred8ta• 13 days ago

Among other things, turbulent currents of liquid iron in the Earth's core can make the core drift eastward or westward, which causes the crust and mantle to turn slower or faster. Same thing with the strength of the jet stream.

layer84• 13 days ago

See https://en.wikipedia.org/wiki/Leap_second#:~:text=Other%20co...

fooqux• 13 days ago

Even the migrations of animals can impact it, although they usually cancel out over the course of a year I think.

0ckpuppet• 13 days ago

I predict there will be a news story or broadcast news pundit who blames this on climate change. bonus points if it winds up on dytime talk shows

hdgvhicv3• 13 days ago

Well melting ice certainly go tributes

ralferoo• 13 days ago

Quite the opposite. The earth's rotation can vary by quite a few seconds each year. But over hundreds of years, the variations mostly cancel out, which is why I think trying to add or remove leap seconds are a bad idea. The only people who care about such things are space agencies, and they can apply whatever offset they want, it doesn't need to affect everyone else.

Arguably, the only real-world impact this drift has on normal people is GPS, but GPS already transmits an offset from its own clock so that receivers can correct for that. The GPS clock is different both from UTC and TIA.

chippiewill2• 13 days ago

the variations mostly cancel out

I don't think we know this do we? we haven't been measuring accurately enough for long enough to be confident that it does in fact cancel out. In fact for the period of time where we've been applying leap seconds they were happening with significant frequency and always in the same direction. It's only been very recently that there's been the realistic suggestion it might drift in the other direction.

If anything people have been suggesting that if we do get rid of leap seconds that we can just wait until the offset is enormous instead (say an hour) because it would take a very long time to happen. But even still, that does actually affect everyday people (because people would surely notice when solar noon is an hour later/earlier). Although pragmatically the obvious solution there is to change timezone instead.

dodoisdodo• 13 days ago

The real Time Variance Authority

KboPAacDA3• 13 days ago

If the UTC-TAI offset remains at -37s, then it also means the UTC-GPS offset remains at -18s. TAI and GPS have a constant 19s offset from each system.

da-x• 13 days ago

My longevity will extend one second into the future in nominal terms, increasing the chance to reach the 22nd century a tiny bit.

clircle• 13 days ago

Cool, I don't have to set my clocks back this December.

ComputerGuru• 13 days ago

This announcement is very much a nothing burger; it’s already been more or less decided that adding leap seconds just isn’t going to be a thing anymore (in our lifetime). Here’s on article from 2022: https://www.timeanddate.com/news/astronomy/end-of-leap-secon...

Surac• 13 days ago

World will end at 26 December so no leap second needed

AbstractH24• 13 days ago

ELI5: How does this impact UNIX timestamps? Particularly for things that are in maintenance mode or otherwise minimally maintained.

Nothing I do requires this level of precision, but certainly there are things that do.

eqvinox5• 13 days ago

UNIX timestamps are fully ignorant of leap seconds, i.e. pretends they don't exist. That means there can be physical seconds of time that cannot be referenced with a UNIX timestamp (when a leap second is inserted) as well as UNIX timestamps for seconds that don't exist (when a leap second is deleted).

aidenn02• 13 days ago

It also means that if you subtract two timestamps, you might not get the actual time between them. Though this is also true of most ways of representing time (TAI being a notable exception).

eqvinox5• 13 days ago

"fully ignorant" might not have been the best wording there...

- clarification: "fully ignorant" from a human perspective, using dates and times. UNIX time lines up with those.

rzzzt2• 13 days ago

Whenever leap seconds were added, Google was running the clocks on their servers slower/faster over a longer period of time (hours) so they would slowly drift back in sync with the solid platinum, perfectly spherical grandfather's clock sitting in NIST or whatever: https://developers.google.com/time/smear

mizmar2• 13 days ago

Yes, time() and clock_gettime(CLOCK_REALTIME) results are affected by leap seconds.

New leap second will get to your system through NTP. Sadly NTP only distributes indicator flag that leap second is going to be introduced, but not the offset itself. But the distributed time itself is already affected by leap second, so NTP client doesn't really need to know.

(In contrast the other time sync mechanisms - GPS and PTP - use time scale unaffected by leap seconds and distribute it as an additional information with UTC offset. And it's left on client to modify received time on its end. Kernel has a parameters in clock_adjtime() for leap seconds.)

So if you have a passive system that has NTP client then it's time will change for new leap second on runtime. Linux treats UTC time as the dominant one, so that's the one saved to RTC device and will survive reboot.

There is CLOCK_TAI that sounds like it should return TAI time, but it is such a second class citizen to the point that nothing on regular Linux desktop and server distros even set the offset and it returns the same time as CLOCK_REALTIME.

There is a file in /etc with list of leap seconds that is part of some package, so you need to update the system to update this file. I don't believe traditional NTP software updates this package dynamically. But not many software uses it. If some init service script parsed and set the kernel UTC offset then your system's CLOCK_TAI would be one second late from rest of the world until update. But it doesn't affect UTC time on Linux in any way I know.

BobbyTables2• 13 days ago

Too expensive in this economy ?

yayamao• 13 days ago

looks like tons of service will crash at the new year eve

gnabgib• 13 days ago

No. Try again

usr1106• 13 days ago

Isn't this anti-news? I vaguely remember they have stopped introducing leap seconds until further notice because they cause too much trouble with today's computing systems. On my phone now and did not research it, as I say vaguely remember. Now we are 37 seconds off. Nobody of us will have to worry that Christmas is around Easter time. We can leave that problem to future generations much more responsibly than many other problems.

That the notice comes every 6 months is just to meet the letter of the original international treaty.

hsbauauvhabzb• 13 days ago

The fact that it’s only 6 months seems insane to me and probably the cause of the problem, if time was +- 60 seconds nobody would notice, so a more manageable solution would be to implement an arbitrary leap about once a decade, with a decades notice so everyone can sort their systems with plenty of notice. 6 months for a world wide coordinated execution is laughably optimistic.

chippiewill2• 13 days ago

No, they haven't done that yet. It's just a proposal, but it's not likely to be formally stopped until 2035.

The reason we've stopped having leap seconds is because the drift between TAI and UT1 slowed down and has actually been very slowly drifting in the other direction.

mimo84• 12 days ago

With the Temporal API will all of the browsers / nodejs etc be able to get the time right when performing operations around that time or will they need to be updated in order to not mess up calculations?

wahern• 12 days ago

Temporal API seems to be based around Unix/POSIX timestamps, which ignore leap seconds. In Unix time a day is always 86400 "seconds". This makes it trivial to do UTC calendar arithmetic into the past and future without recourse to a database and without necessarily having to deal with fractional seconds. Leap seconds are handled by the OS by repeating or skipping a second, or slewing the length of a second for some period before and after the leap second.

Most datetime APIs are fundamentally designed and intended for supporting calendar and wall clock operations for business functions. If you need SI seconds for scientific purposes, you really need to use alternative APIs and facilities that provide and guarantee the semantics required all the way down to the hardware level. Likewise, if you want timers, etc, for software facilities like thread sleeping, you use dedicated interfaces like monotonic clocks. If leap seconds are phased out, this won't really change the situation. It was wrong for software to rely on Unix timestamps for, e.g., mutex algorithms before and it'll be wrong if and when leap second clock adjustments are gone.

mayhemducks• 12 days ago

The man with more than one watch never knows what time it is.

No leap second will be introduced at the end of December 2026

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