World Timekeeping Authorities Vote to Abolish the Leap Second

After three decades of debate, the world's official timekeeping authorities have voted to end the use of the leap second, replacing it with a far less frequent adjustment known as the leap hour. The decision was taken at the General Conference on Weights and Measures in Versailles, France, where delegates from 69 countries cast their votes.

The leap second has been used for decades to keep Coordinated Universal Time (UTC) aligned with time measured according to the Earth's rotation, since the planet's rotation is slightly irregular and gradually drifts out of sync with atomic time. Under the new system, set to take effect on 20 May 2027, UTC will instead run continuously, with the allowed difference between atomic time and astronomical time extended to a full hour rather than a single second.

Dr Setnam Shemar of the UK's National Physical Laboratory said: 'After 30 years of debate, the leap second is making way for the leap hour.' Noël Dimarcq of the French National Centre for Scientific Research, who chairs the International Bureau of Weights and Measures' Consultative Committee for Time and Frequency, stated: 'After 30 years of debates, we are ready.' The change is intended to reduce the risk of computer systems and other technical infrastructure malfunctioning when forced to process minutes of unusual length, a concern that has become more pressing as global technology increasingly depends on precise, uninterrupted timekeeping.