Scientists are delaying the start of the New Year by adding the first leap second in seven years to keep clocks in sync with solar time used by astronomers.
The Paris Observatory said an extra second would be added to clocks worldwide at the stroke of midnight on 31 December.
"Enjoy New Year's Eve a second longer," said the researchers at the US National Institute of Standards and Technology. Tidal friction The International Earth Rotation and Reference Systems Service, based at the Paris Observatory, tells the world every six months whether to add or subtract a second from atomic clocks, the standard for everyday timekeeping.
A leap second is added to Coordinated Universal Time (UTC) to keep it in step with solar time - based on the Earth's rotation on itself - to within a second.
Tidal friction causes the Earth's rotation to slow down, which means that solar time tends to drift out of sync with atomic clocks. If this disparity was not corrected, the error could increase to several seconds within a few decades; and would very quickly make software and possibly hardware used by astronomers obsolete.
There have been 22 leap seconds added - and no subtractions - since the first one on 30 June, 1972.