In short, the official time will actually go from 23:59:59 to 23:59:60 instead of directly to 00:00:00.
How does Windows react to the extra Leap Second added
The Windows Time Service maintains the date and time synchronization on all clients and servers in the network.
When the Windows Time service is working as a Network Time Protocol (NTP) client:
When the Windows Time service is working as an NTP server:
I suppose most of us will not worry too much over it, but for those fastidious ones – you might want to update the times of your computer, smartphone, or your wristwatch!
