Most clocks will just ignore the leap second, but Time.is counts all the way up to 60 seconds!
The leap second does not occur on December 31 everywhere! The date and time depends on your time zone. In New York the leap second will occur at 06:59PM:60 on Saturday, December 31, 2016. To find out what time the leap second will occur in other locations, use the search box above.
Remember to set your clock one second back after the leap second!