AWS Blog

Look Before You Leap – December 31, 2016 Leap Second on AWS

by Jeff Barr | on | in Amazon EC2, Amazon RDS, Announcements |

If you are counting down the seconds before 2016 is history, be sure to add one at the very end!

The next leap second (the 27th so far) will be inserted on December 31, 2016 at 23:59:60 UTC. This will keep Earth time (Coordinated Universal Time) close to mean solar time and means that the last minute of the year will have 61 seconds.

The information in our last post (Look Before You Leap – The Coming Leap Second and AWS), still applies, with a few nuances and new developments:

AWS Adjusted Time – We will spread the extra second over the 24 hours surrounding the leap second (11:59:59 on December 31, 2016 to 12:00:00 on January 1, 2017). AWS Adjusted Time and Coordinated Universal time will be in sync at the end of this time period.

Microsoft Windows – Instances that are running Microsoft Windows AMIs supplied by Amazon will follow AWS Adjusted Time.

Amazon RDS – The majority of Amazon RDS database instances will show “23:59:59” twice. Oracle versions 11.2.0.2, 11.2.0.3, and 12.1.0.1 will follow AWS Adjusted Time. For Oracle versions 11.2.0.4 and 12.1.0.2 contact AWS Support for more information.

Need Help?
If you have any questions about this upcoming event, please contact AWS Support or post in the EC2 Forum.

Jeff;