End of the leap second: UTC world time will run without extra seconds from May 2027
The General Conference on Weights and Measures decided in Versailles that no leap seconds will be added from May 20, 2027. The International System of Units is also to go digital.
Archive image · Photo: Pressestelle PTB / Wikimedia Commons, CC BY-SA 4.0 (cropped and resized)
The 28th General Conference on Weights and Measures (CGPM) met in Versailles from October 13 to 15 and adopted seven resolutions on its final day, Germany's national metrology institute PTB said. One concerns world time: Coordinated Universal Time (UTC) will run without leap seconds from May 20, 2027. The date coincides with World Metrology Day, which marks the signing of the Metre Convention in 1875.
Until now, leap seconds have kept atomic time in step with Earth's irregular rotation. In future, the difference between the two may grow to as much as one hour. According to PTB, this also removes the risk of a first-ever negative leap second, meaning a second that would have to be subtracted.
The conference also backed a machine-readable, digital International System of Units (SI) and a digital reference framework for the services of national metrology institutes. A new observer status was created for non-member states that use SI and UTC and for organisations such as the World Meteorological Organization. PTB President Cornelia Denz was re-elected to the International Committee for Weights and Measures (CIPM).