Overview
- The Generalkonferenz für Maß und Gewicht voted to stop inserting leap seconds and to start a continuous UTC on 20 May 2027, making routine one‑second jumps in civil time history.
- Under the new rules UTC may differ from astronomical time (UT1) by up to 3,600 seconds before any large correction is considered, a tolerance intended to avoid frequent, risky time edits.
- The decision was driven by recent shifts in Earth’s rotation that raised the chance of a first negative leap second and by repeated operational problems, such as server crashes and synchronization errors in finance and networks, caused by past leap seconds.
- Separately, metrology bodies will pursue a possible redefinition of the second based on much more precise optical atomic clocks and plan to deliver a concrete proposal to the 2030 CGPM while work continues on comparisons, signal distribution and gravity‑related corrections.
- For most people the change will be invisible, but it matters for astronomy, geodesy, satellite navigation and emerging lunar infrastructure, and experts say any required large correction would not be needed for many centuries.