Overview
- The Generalkonferenz für Maß und Gewicht (CGPM) decided Thursday to stop inserting leap seconds and to put a continuous UTC into effect on 20 May 2027.
- Under the resolution, UTC may be allowed to diverge from astronomical time (UT1) by up to 3,600 seconds before any correction is applied.
- Delegates cited risks that single‑second insertions or removals can disrupt software, networks and critical infrastructure and that models showed roughly a 30 percent chance of a negative leap second by 2035.
- The Bureau International des Poids et Mesures (BIPM) will continue a scientific roadmap toward a possible redefinition of the second using optical atomic clocks, with no formal proposal expected before the 2030 conference because international comparisons and relativistic corrections still need resolution.
- Everyday clocks and civil timekeeping will largely be unaffected while astronomers and precision users will keep access to UT1 and specialist systems must adapt to the longer, gradual offset and existing differences in how services like GPS and GLONASS handle leap seconds.