Overview
- The General Conference on Weights and Measures voted to stop inserting leap seconds and to run Coordinated Universal Time continuously starting May 20, 2027, removing the routine one‑second adjustments used since 1972.
- The permitted difference between atomic UTC and Earth‑rotation UT1 was increased from 0.9 seconds to 3,600 seconds so UTC can remain continuous for centuries without frequent corrections.
- The CGPM set a target to redefine the SI second by 2030 using optical atomic clocks, with options under discussion that include a single optical transition or a weighted multi‑frequency standard.
- The conference also recommended creating a coordinated lunar timescale based on IAU Lunar Coordinate Time to support precise navigation and operations on the Moon under different gravity and motion conditions.
- Operators of data centers, telecom networks, satellite systems and power grids are preparing technical changes because leap seconds have previously caused systems outages and special handling, and the new rule should simplify timekeeping but require multi‑year transitions.