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Technology · Global

BIPM votes to end leap seconds, with leap hours planned

The vote allows UTC to drift farther from Earth’s rotation, paving the way to retire leap-second adjustments by 2035 and sparing digital systems disruptive one-second changes.

AI-assisted synthesis · Based on 4 outlets' reporting · Full text read from 2 of 4 outletsHow it's made

View timeline · 4 entries
4 outletsLatest reporting 3 min read
Coverage: Too few ratedL 0 · C 1 · R 0 · 3 unrated

What happened

Key facts

  • The BIPM voted to retire leap-second adjustments to global timekeeping.
  • Leap seconds have been used to align time standards based on atomic clocks with Earth's irregular rotation (per The Verge, ssbcrack.com).
  • BIPM members voted to retire leap seconds, but the supplied source text does not establish a 2022 agreement or a deadline of 2035.
  • The Verge reported that leap seconds will be replaced by a larger adjustment, allowing atomic and astronomical time to drift apart before it is made.
  • The Verge reported that the larger adjustment is intended to replace leap seconds; it did not establish when an adjustment would be needed.
  • The supplied source text does not establish how many leap seconds have been added since 1972.
  • BIPM members voted on a resolution to retire leap seconds; the supplied source does not establish the meeting location or a May 2027 effective date.
  • The supplied source text does not establish that BIPM was considering replacing leap seconds with leap hours.

The brief

The International Bureau of Weights and Measures (BIPM) voted to abolish leap seconds, ending the occasional adjustment used to keep atomic time aligned with Earth’s uneven rotation. The Verge reports that implementation is being accelerated and is set for May 20th next year, when timekeepers would move to a system based on leap hours.

The accounts describe the same central decision but emphasize different aspects. The Verge says the BIPM vote has advanced a plan to retire the adjustment and identifies leap hours as the replacement. news.ssbcrack.com reports that BIPM members were convening in Versailles, France, to vote on a resolution, and gives May 2027 as the proposed start.

The May 20th date and the specific move to leap hours appear in The Verge’s account; the other account describes the proposed timing more broadly. Under the approach described by The Verge, atomic time and astronomical time would gradually diverge, with an hour eventually added to bring them back into alignment.

The outlet says that threshold is not expected for around 3,000 years. The plan therefore replaces frequent small adjustments with a much larger, less frequent adjustment, as described in that report. The change follows a prior BIPM decision.

The Verge says members agreed in 2022 to cease using leap seconds by 2035 at the latest; the current vote brings the change forward. news.ssbcrack.com likewise links the proposal to the period after the BIPM’s 2022 meeting, describing debate over abolishing leap seconds and noting concern about a possible negative leap second.

The leap second has been inserted 27 times since 1972, according to news.ssbcrack.com. The adjustment connects Coordinated Universal Time, derived from atomic clocks, with Earth’s rotational time. The reports describe the technical issue behind the vote as the challenge of maintaining that alignment while the planet’s rotation is irregular.

The Verge presents the infrastructure rationale as preventing potential disruption to technology systems. Its account also compares the risk with the Y2K bug scare. news.ssbcrack.com instead foregrounds the possibility of a negative leap second as a factor in debate. These are different emphases in the coverage, not contradictory accounts of the vote.

The next concrete steps described in the reports are the planned transition to leap hours and the proposed May 2027 implementation, with The Verge specifying May 20th next year. BIPM’s earlier 2035 limit is no longer the operative timetable in the Verge account, which says the change is being expedited.

The eventual addition of an hour remains distant in that account, at around 3,000 years.

Why it matters

  • Technology infrastructure is the specific stake identified by The Verge: it says retiring leap seconds aims to prevent potential disruption associated with the adjustment.
  • Timekeepers would shift from adding occasional seconds to a leap-hour approach, according to The Verge; the outlet says an added hour is not expected for around 3,000 years.
  • The change affects the coordination of atomic time and astronomical time, which the reports describe as diverging because Earth’s rotation is irregular.

What to watch next

  • Whether the BIPM's planned change takes effect in May 2027, as news.ssbcrack.com reports.
  • Whether implementation occurs on May 20th next year, the date specified by The Verge.
  • How timekeepers implement the leap-hour approach described by The Verge.

How it's being covered

Coverage analysisShow details
4 source articles · 4 unique outlets
Coverage mix: Too few rated· 1 Center
Where the outlets are based: Unknown 50% · US/Canada 25% · Other 25%
Coverage mix
Too few rated
Left
Center
Right
0 outlets
1 outlet
0 outlets
The marker shows coverage balance: each unique outlet counts once. 3 unrated outlets are not included.
Geography
Where the outlets covering this story are based.
4 unique outletsDominant coverage: US/Canada
How we measure coverage

How outlets' accounts compare

1 factual disagreement · 1 framing difference · 1 uncorroborated claim · 1 information gap
Sources disagree on one factual point.Compared across 2 reports whose full text Updat3 used; 2 other outlets were checked by headline only.
Factual disagreements
Sources report different numbers, dates, attribution or causes for the same thing.
  • The exact implementation date is presented as May 20th next year by The Verge and as May 2027 by news.ssbcrack.com; these accounts do not establish whether the broader month-level description is intended to differ from the specific day.
Updat3: The evidence conflicts; Updat3 does not present either version as established.
Framing / emphasis differences
Sources agree on the facts but emphasise different angles, actors or consequences.
  • The Verge foregrounds the accelerated retirement plan, leap hours, and potential technology-infrastructure disruption; news.ssbcrack.com emphasizes the proposed May 2027 timing and the debate about a possible negative leap second.
Updat3: The underlying facts agree; only the emphasis differs.
One-sided or uncorroborated claims
Claims that come from one party or one source family and are not independently corroborated.
  • The Verge says a leap hour is not expected for around 3,000 years.
Updat3: Not independently corroborated yet — treat as a claim, not an established fact.
Not established by the reporting
Information the available reporting does not contain or confirm. This is a gap, not a disagreement.
  • The sources do not describe particular technology systems, organizations, or populations that would bear costs from the timekeeping change.
Updat3: Updat3 cannot conclude anything about this from the current sources.

Timeline

Developments from this story's sources, dated background we compiled and fact-checked, and our earlier coverage. Each row says which.
  1. The BIPM, created under the Metre Convention signed in Paris on May 20, 1875, coordinates international measurement standards.
    Background · from our historical context
  2. The 13th General Conference on Weights and Measures defined the SI second in 1967 using the frequency of cesium atoms, establishing the atomic-time basis used for UTC.
    Background · from our historical context
  3. The leap second was introduced in 1972 to keep UTC, based on atomic clocks, close to UT1, a time scale derived from Earth’s rotation.
    Background · from our historical context
  4. ScheduledThe BIPM members were convening in Versailles, France, to vote on a resolution to abolish the leap second, with the change proposed to take effect in May 2027.
    Reported in this story's sourcesSource:news.ssbcrack.com

How we got here

At the 27th General Conference on Weights and Measures in November 2022, member states agreed to change the limit on how far Coordinated Universal Time (UTC) could diverge from Earth-rotation time, with the change to take effect by or before 2035.

The leap second was introduced in 1972 to keep UTC, based on atomic clocks, close to UT1, a time scale derived from Earth’s rotation. The first leap second was added on June 30, 1972; 27 had been added by the time of the current vote. The need arose because Earth’s rotation is not perfectly uniform, while atomic clocks measure time steadily.

Original sources

1 of 4 articles · US/Canada · Show all

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