On a digital clock, a leap second reads 23:59:60 or 11:59:60 pm. They occur at the end of the day, just before the clock ticks over to midnight. Leap seconds are traditionally added either on June 30 or on December 31. However, the Earth's rotation speed fluctuates constantly, so the actual frequency of leap seconds can vary. The difference grows to one second in about 1.5 years. About One Second Every 1.5 YearsĪn average Earth day is about 0.002 seconds longer than 24 hours. The speed at which our planet rotates around its axis fluctuates daily, and it slows down very slightly over time.īy adding an extra second to the time count, we effectively stop our clocks for that second to give Earth the opportunity to catch up.Īdding a leap second creates a minute with 61 seconds-and a day with 86,401 seconds instead of the usual 86,400. We add leap seconds from time to time to ensure our clocks reflect the Earth's rotation speed as accurately as possible.

In any case, we will publish the date of the next leap second here as soon as it has been officially announced.Įarth sets new record for shortest day Why Do We Need Leap Seconds? However, the Earth's rotation has been relatively fast lately, so it is unlikely that any leap seconds will be added in the near future. The next possible date is December 31, 2023. Latest update: In January 2023, the International Earth Rotation and Reference Systems Service (IERS) announced that “NO leap second will be introduced at the end of June 2023.” Business Date to Date (exclude holidays)Ītomic clocks don't take into account the Earth's slowing rotation.

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