BIPM moves to end leap seconds from May 20 next year

The International Bureau of Weights and Measures (BIPM) voted to end the use of leap seconds from May 20 next year, bringing forward a plan its members agreed to in 2022. The date coincides with World Metrology Day.

Leap seconds are occasional adjustments that keep tracked time standards aligned with Earth’s irregular rotation. The change aims to avoid potential infrastructure failures linked to adding or subtracting seconds. Shifts in Earth’s rotation may soon require timekeepers to subtract time to keep astronomical time aligned with atomic time, a step never attempted before.

Concerns about the effects on critical infrastructure follow past outages at Foursquare, Reddit, LinkedIn, Yelp, and other technology platforms when leap seconds were added. Meta, Google, Microsoft, and Amazon have supported efforts to end the system.

Under the new approach, timekeepers will use “leap hours,” allowing atomic and astronomical time to drift gradually. An adjustment of an entire hour is not expected for around 3,000 years.