The world's timekeepers will stop adding leap seconds in 2027

Worldwide

The International Bureau of Weights and Measures said on Thursday it will stop issuing leap seconds on May 20, 2027, the anniversary of the Metre Convention.

Leap seconds added since 1972

32 seconds

Since 1972, 32 leap seconds have been added to Coordinated Universal Time to keep atomic clocks in step with Earth's slowing rotation. The last one came in 2016.

Why it matters

Leap seconds have disrupted computer systems that run on UTC, and Earth's faster spin in recent years raised the odds of a first negative leap second, which had never been tested.

"The probability of a negative leap second convinced us [to] set the application date in 2027."

— Patrizia Tavella, BIPM time department director