Particle.news
Get it on Google Play
Download on the App Store
10 ARTICLES
·
6d ago

Global Timekeepers Vote to End Leap Second and Adopt a Leap Hour

The CGPM made UTC continuous, allowing up to a one-hour divergence from Earth rotation to reduce the risk of disruptive one-second adjustments to digital systems.

A timekeeping change could reshape how the world measures time.
Image
Leap seconds have kept our clocks more or less aligned with astronomical time.
Image

Overview

  • Member states at the General Conference on Weights and Measures voted on 15 October 2026 to retire the leap second and replace it with a leap-hour framework.
  • The resolution takes effect on 20 May 2027, when Coordinated Universal Time (UTC) will be published as a continuous scale without leap-second insertions.
  • Timekeepers said the move aims to prevent recurring outages and software failures historically linked to leap seconds, citing past incidents at LinkedIn, Reddit, Cloudflare and airline booking systems.
  • Under the new rule UTC may drift up to 3,600 seconds from astronomical time (UT1) before a corrective leap hour is applied, while IERS will continue to monitor and publish UT1–UTC differences and operators must update legacy systems and some satellite-navigation platforms.
  • Delegates also discussed longer-term technical changes, including redefining the second with optical clocks and a possible lunar time standard, and experts say a leap hour is unlikely to be needed for centuries, shifting practical fixes to future generations.