Overview
- The General Conference on Weights and Measures approved ending leap-second insertions and removals and will operate a continuous Coordinated Universal Time (UTC) beginning 20 May 2027.
- The permitted difference between atomic time (UTC) and Earth-rotation time (UT1) has been raised from 0.9 seconds to 3,600 seconds, allowing civil time to slowly drift up to one hour from solar time.
- National labs and standards bodies cited repeated technical problems when seconds were inserted and warned that a never-before-used negative leap second (removing a second) would add new risks for servers, telecom networks, satellite navigation and power systems.
- The CGPM set a target to redefine the second by 2030 using optical atomic clocks, with options under discussion that include a single optical transition or a weighted mean of multiple frequencies.
- The conference also endorsed development of a lunar timescale based on the IAU's TCL, and officials say ordinary wristwatches, phones and radio clocks will not need user changes while specialized technical systems will update their timing practices.