A leap second is being added to the end of Saturday, June 30, which will result in the clock actually reading 23:59:60. (Time.is)
(WXIA) -- It's official - June 30 will be the longest day of the year. One second longer, to be exact.
An extra second, called a "leap second," will be added to the end of the day on Saturday, resulting in a day that is one second longer than each and every other day of the year.
As a result, the final second of the day on Saturday, June 30 will be 23:59:60, instead of the more customary 23:59:59.
The second is added by the International Earth Rotation and Reference Systems Service (IERS), which is the coordinating body that tracks and maintains global time standards. The service was established in 1987 to maintain tracking of time and linking it to the rotation of the Earth.
Leap seconds have been added by IERS and its predecessor body the BIH, some 24 times since 1972, to more align the primary standard of time measurement -- called Coordinated Universal Time -- with the rotation of the planet.
The last leap second that was added to the clock was on December 31, 2008. The next one has not been announced. IERS generally only announces the placement of leap seconds about 6 months in advance, due to the nature of the rotation of the Earth.