Time’s up for the leap second as scientists swap it for the leap hour
International timekeeping authorities have voted to replace the leap second with a leap hour to prevent technical errors in global computer systems. This change, effective next year, allows for greater drift between astronomical time and coordinated universal time.
Why it matters
The leap second has historically caused significant glitches in digital infrastructure; this shift provides a more stable, albeit infrequent, adjustment method for global timekeeping.
A clock at the Royal Observatory, Greenwich, through which the prime meridian passes. A clock at the Royal Observatory, Greenwich, through which the prime meridian passes. Science How an accelerating Earth led experts to adopt the leap hour International delegates agree leap second no longer tenable, but first leap hour not likely to happen for thousands of years
Ian Sample Science editor Thu 15 Oct 2026 17.16 BST Last modified on Fri 16 Oct 2026 05.22 BST Share Prefer the Guardian on Google A fter decades of discussion, quibbling and worrying about clocks in computer systems, the world’s official timekeepers have voted to replace what many viewed as a tiresome correction: the leap second. It’s time, they say, for the leap hour.
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