A leap second will be inserted into global time scales at 9 a.m. Wednesday.
 
A leap second is added to correct for minor discrepancies between Universal Time, which is defined by the Earth's rotation, and International Atomic Time, determined by atomic clocks in laboratories around the globe.
 
The one-second adjustment will keep broadcast standards for time of day close to Universal Time.
 
The planned insertion will be the 26th since 1972 and the first since July 1, 2012.
 
The leap second will be automatically applied to mobile phones.