Retiring the Leap Second Is Still Work

The International Bureau of Weights and Measurements, known as BIPM, said Thursday that it would stop issuing leap seconds in May 2027, Wired reports. The change concerns Coordinated Universal Time, or UTC, the shared time standard used by databases, APIs, and other computing systems. The announcement sets a future transition. It does not mean every system has already stopped accommodating the extra second.

The world introduced leap seconds in 1972 to reconcile two ways of keeping time. Atomic clocks provide one measure; observations of Earth’s rotation provide another, called UT1. Earth does not rotate with the uniformity of an atomic clock. Tidal friction, the oceans, the atmosphere, and the planet’s molten core influence its spin. Adding a second allowed UTC to remain aligned with astronomical time. The most recent addition, according to Wired, came in 2016.

That reconciliation served a purpose, but computers did not always receive it gracefully. Wired reports that a leap second disrupted Qantas’s booking system in 2012. An ordinary attempt to reserve a flight is a useful measure of the stakes: the correction may be obscure, but a booking system’s failure is not. The clock’s smallest adjustment has generated a substantial meeting agenda.

Operators developed ways to manage the interruption. Google and Meta use a “smear” method, spreading the adjustment across roughly a day in small increments, according to the explanation Wired obtained from Judah Levine of the US National Institute of Standards and Technology. That workaround shows companies adapting to a shared convention. It does not, by itself, show that those companies controlled the decision to retire it. Their practical difficulties belong in the history without becoming the whole explanation.

Retirement can therefore be useful change rather than genuine loss. Stopping leap seconds does not stop Earth’s irregular rotation, and it does not eliminate the need for a common clock. It changes how institutions manage the relationship between the two measures. Wired also identifies the possibility of a first negative leap second as a concern behind the change. Avoiding another kind of correction may remove a problem, but the announced May 2027 schedule still leaves implementation work ahead.

For institutions maintaining time services, the task is less ceremonial than the word “abolished” suggests. Operators need to establish how their systems handle the transition and whether connected services follow compatible arrangements. They also need to retain records of earlier corrections and workarounds so future maintainers can understand older behavior. The useful inheritance is not the extra second itself. It is the expertise, documentation, and coordination that keep a flight reservation ordinary.