No Leap Second Will Be Added in December 2026

The International Earth Rotation and Reference Systems Service (IERS) has published its latest Bulletin C, which indicates that no leap second will be added at the end of December 2026.

Leap seconds are used to keep Coordinated Universal Time (UTC), which is based on atomic clocks, in sync with the actual rotation rate of the Earth, which is subject to small fluctuations. The decision on whether an adjustment is needed is made by the IERS twice a year — ahead of the end of June and ahead of the end of December.

The news drew a notable response in the Hacker News community, where the discussion racked up 153 points and more than a hundred comments. The topic of leap seconds has always attracted the attention of developers and system administrators, since adding one can cause failures in software that relies on system time working precisely and predictably.

In recent years there has also been discussion of a more radical step — abolishing the practice of leap seconds altogether in the future in favor of other synchronization mechanisms, though a concrete decision on that transition has been deferred to a later date.

Source: Hacker News