A "leap" second will be added at 23:59:60 UTC (Coordinated Universal Time), and it works the same way as February 29 does in a leap year.
The extra second is added in order to synchronize atomic clocks with astronomical time.
"Earth's rotation is gradually slowing down a bit, so leap seconds are a way to account for that," Daniel MacMillan of NASA's Goddard Space Flight Center said.
A total of 25 leap seconds have been added since 1972.
So, what will you do with your extra second? Get some ideas from John Oliver at spendyourleapsecondhere.com.
Copyright 2015 FOX 11 Los Angeles | Download our mobile app for breaking news alerts or to watch FOX 11 News | Follow us on Facebook , Twitter and YouTube.