Leap seconds is a one-second adjustment that is occasionally applied to Coordinated Universal Time
) in order to keep its time of day close to the mean solar time, or UT1.
Without a Leap seconds correction, time reckoned by Earth's rotation drifts away from atomic time because of irregularities in the Earth's rate of rotation. Since this system of correction was implemented in 1972, 27 leap seconds have been inserted, the most recent on December 31, 2016 at 23:59:60 UTC.
There might be more information for this subject on one of the following:
- - Leap_second - based on information obtained 2017-03-08-