Few people know, but 2017 will come a second later. On New Year's Eve, an additional 61st second will be added to UTC. This was reported by the International Earth Rotation Service.
It's all about the UTC standard - Coordinated Universal Time. In accordance with it, the period of the Earth's revolution around its axis is 24 hours or 86400 seconds. But in fact, it lasts 86400, 002 seconds, that is, two thousandths of a second longer. It is easy to calculate that an extra astronomical second accumulates in a year. To compensate for this "increase" and charge the coordination (leap) second.
According to the established rule, the addition is made at midnight on the last day of June or December.