No Leap Second Scheduled for December 2026

The International Earth Rotation and Reference Systems Service (IERS) has officially confirmed that no leap second will be added to Coordinated Universal Time (UTC) at the end of December 2026. This decision ensures that the difference between UTC and International Atomic Time (TAI) remains at -37 seconds.

UTC and TAI Time Synchronization

As of January 1, 2017, and continuing through the end of December 2026, the offset between Coordinated Universal Time (UTC) and International Atomic Time (TAI) is exactly 37 seconds (UTC-TAI = -37 s). This offset is maintained to keep UTC aligned with the Earth's rotation, which is slightly irregular compared to the precise ticking of atomic clocks.

Leap Second Implementation Process

Leap seconds are introduced into UTC at the end of June or December based on the evolution of UT1-TAI. The IERS manages this process through the publication of Bulletin C, which is issued every six months to either announce a necessary time step or confirm that no adjustment is required for the next possible date.

According to Bulletin C 72, published on July 6, 2026, the Earth's rotation does not currently necessitate a time adjustment for the upcoming December window.