CGPM Votes to End Leap Second Insertions into UTC After 2035

Delegates from the International Telecommunication Union and Bureau International des Poids et Mesures met in Versailles and passed a resolution ending the irregular insertion of leap seconds into UTC. The decision follows documented cases where leap seconds caused software crashes in financial trading platforms and navigation systems that assume continuous time. Twenty-seven positive leap seconds have been added since 1972 to keep UTC within 0.9 seconds of Earth rotation, but the accumulating offsets have grown operationally costly for global infrastructure.

Continuous atomic time will now run without interruption, decoupling civil time from astronomical day length. This shift directly benefits high-precision applications in radio astronomy, satellite laser ranging, and deep-space navigation where even one-second discontinuities require custom handling code. Systems such as GPS and BeiDou already operate on their own continuous scales; the new UTC rule aligns legal timekeeping with those engineering realities rather than forcing repeated patches.

The change challenges the long-held assumption that civil time must track solar time at sub-second precision. Over decades, the divergence between atomic seconds and mean solar days will reach several minutes, forcing periodic debates about redefining the second or introducing a new leap-minute mechanism. No such adjustment is scheduled before 2135 under the current resolution.

National metrology institutes must now update legal references and test software stacks for the post-2035 regime. The BIPM will publish a final leap-second bulletin in 2034 confirming the transition to an uninterrupted atomic timescale.