World timekeepers have voted to end leap seconds, with continuous UTC due to take effect on 20 May 2027. The move is meant to avoid computer problems caused by tiny time adjustments, even though UTC will drift from Earth’s rotation.
01Summary
- 01The General Conference on Weights and Measures voted on Thursday to abolish the leap second.
- 02The official end date is 20 May 2027, when continuous UTC becomes effective.
- 03Leap seconds were added to UTC in 2012, 2015 and 2016, and 2012 caused crashes affecting Reddit, LinkedIn and Mozilla.
- 04The conference said there is a 30% chance a negative leap second may be needed by 2035 if UTC stays aligned with rotational time.
- 05The CGPM said UTC can drift from rotational time by up to an hour for several centuries while remaining stable.
02Why it matters
This changes how global clocks are kept in sync and removes a source of rare but serious software disruption. It matters most for systems that depend on precise timing, including transport, energy, telecommunications and space projects.
Answers are generated by AI from the story summary; they are not investment, health or legal advice.



