Leap Second Historical Log

Review all the dates where the IERS added an artificial leap second to UTC.

Leap Second Log

Earth rotation shifts.

Historical Leap Seconds (UTC)
1972-06-30
1972-12-31
1973-12-31
1974-12-31
1975-12-31
1976-12-31
1977-12-31
1978-12-31
1979-12-31
1981-06-30
1982-06-30
1983-06-30
1985-06-30
1987-12-31
1989-12-31
1990-12-31
1992-06-30
1993-06-30
1994-06-30
1995-12-31
1997-06-30
1998-12-31
2005-12-31
2008-12-31
2012-06-30
2015-06-30
2016-12-31
* The IERS has announced plans to discontinue the leap second system by 2035.

Overview

The nuances of atomic vs solar time.