Leap Seconds to Be Abolished in 2027

The International Bureau of Weights and Measures (BIPM) has officially decided to phase out leap seconds, ending a practice that has been in place for over 50 years. The decision was made at a meeting in Versailles, France, on October 15, and the change will be implemented on May 20, 2027. Leap seconds were introduced to reconcile the highly precise Coordinated Universal Time (UTC), measured by atomic clocks, with astronomical time based on Earth's irregular rotation.

Since their introduction in 1972, 27 leap seconds have been added to UTC, typically at the end of June or December. While these adjustments are imperceptible to humans, they have frequently caused significant system failures for modern technology. For instance, the 2012 leap second adjustment led to outages at services like Reddit and LinkedIn, and Cloudflare experienced disruptions in 2016.

Major technology companies, including Meta and Google, have long advocated for the abolition of leap seconds, citing them as a major operational challenge. Under the new system, the cumulative difference between UTC and astronomical time will be allowed to expand up to one hour before a correction, termed a "leap hour," is implemented. Experts estimate that such a deviation would take over 3,000 years to accumulate.