World timekeepers back future leap hour
How an accelerating Earth led experts to adopt the leap hour
Friday, 16 October 2026
Photo by Catrina Carrigan on Unsplash
Warm-up
- How do you check the time each day?
- Have you ever changed clocks for daylight saving?
- Why do computers need very accurate time?
Vocabulary
- adopt
- to start using a plan or rule officially
- delegate
- a person chosen to represent a country or group at a meeting
- rotation
- the act of turning around a centre; Earth’s daily spin
- atomic
- relating to atoms; here, used for very accurate clocks
- precise
- exact and correct, with very small errors
- drift
- to move slowly away from the correct position or time
- infrastructure
- the basic systems a country needs, like power and networks
- probability
- the chance that something will happen, shown as a percentage
Reading
Listen to this story
British EnglishDelegates from 69 countries met in Versailles, France, at a conference of the International Bureau of Weights and Measures and voted to replace the leap second with a leap hour. The change will be adopted from next year to protect computers and national infrastructure from timing problems.
Under the new plan, Coordinated Universal Time (UTC) may drift by up to one hour from astronomical time before a leap hour is used. Experts say that step will not be needed for thousands of years. Dr Setnam Shemar of the UK’s National Physical Laboratory welcomed the move and compared it to daylight saving.
Since 1972, officials have added 27 leap seconds because Earth’s rotation is irregular. Atomic clocks are far more precise: one second is 9,192,631,770 vibrations of the caesium atom. Recently, the rotation sped up, creating a 30% probability of a first negative leap second in the next decade, which pushed the vote forward.
Comprehension
- Who decided to replace the leap second with a leap hour?
- When will the new system start to be used?
- How far may UTC drift before a leap hour is added?
- How many leap seconds have been added since 1972?
- What recent risk pushed the vote forward?
Grammar focus
Future continuous
Use will be + verb-ing for an action in progress at a specific future time or a temporary future activity. Form: will be + -ing (will be testing, will be reviewing). (Examples constructed.)
- Next year, experts will be adopting a leap hour.
- At this time tomorrow, systems will be syncing with UTC.
Grammar exercise
Complete the sentences with the future continuous form.
- Next year, many labs (monitor) ___ UTC drift.
- At midnight tomorrow, systems (update) ___ security logs.
- This time next week, technicians (compare) ___ atomic clocks.
- In a few years, engineers (adjust) ___ software for leap hours.
- Tomorrow afternoon, servers (coordinate) ___ backup timing.
Discussion
- Is a leap hour better than a leap second? Why?
- How could time changes affect travel or daily life?
- Should timekeepers prioritise technology needs or tradition?
- Is comparing a leap hour to daylight saving helpful? Why?
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