Leap second

A leap second is characterized by a specific situation. Commonly, a minute lasts 60 seconds, but when a leap second occurs, 1 minute lasts either 61 seconds or 59 seconds. The leap second is applied occasionally without specific planning. This decision is made by the IERS to accommodate the difference between the high-precision atomic clock time and solar time that reflects the natural Earth’s movement (commonly referred to by the abbreviation UT1). As stated, the common reference in civil environments is UTC; however, as the Earth’s rotation speed varies according to climate and geological events, it is necessary to apply a leap second occasionally to ensure the difference between UTC and UT1 does not exceed 0.9 seconds. Typically, the leap second announcement is made approximately six months before its physical occurrence. It is commonly associated with the last day of the month. June or December is preferred if a leap second needs to be applied to a year...