Leap Second Proposal Will Keep Software Stacks in Sync
NetworkWorld, Wednesday, September 9th, 2026
A vote in October could end leap second adjustments from May 2027, sparing systems a never-tested negative leap second.
The General Conference on Weights and Measures votes in October on eliminating leap second adjustments starting 20 May 2027. The urgency is that Earth's rotation has accelerated, making a negative leap second possible for the first time, and no computer system has ever handled one.
Previous positive leap seconds caused widespread outages across Linux kernels, Java runtimes and network stacks, so an untested negative adjustment is a serious operational risk.
The proposal maintains continuous Coordinated Universal Time instead. For infrastructure teams this is a rare case where a standards vote removes a latent failure mode rather than adding work.