The technical actions needed to ensure the continuity of UTC

The International Bureau of Weights and Measures formally resolved that Coordinated Universal Time (UTC) will become a continuous time scale effective 20 May 2027, eliminating future leap second insertions. The maximum allowed difference between UT1 and UTC will be raised to 3,600 seconds (1 hour), ensuring continuity for several centuries. The decision follows concerns from ITU-T, URSI, IEEE 1588 working groups, and industry that a negative leap second—never previously applied—poses high risk to critical infrastructure like IoT, smart grids, telecommunications, and transportation systems, with a CCTF/IERS workshop estimating a 30% probability of needing one by 2035. The BIPM will continue collaborating with ITU, IAU, IUGG, and IERS to support the transition and monitor UT1-UTC divergence.

Source: https://www.bipm.org/en/cgpm-2026/resolution-5. 8 Sync News only summarizes and links out; content copyright belongs to the authors and original sources.