Formally on June 30 after time 23:59:59 will be a time of 23:59:60, and then will start on 1 July. The so-called "second coordinate" will appear automatically on all your devices with external synchronization.
 

Now a second coordinate are added every 3-4 years, however, due to the slowing rotation of the earth, to do it more often.
 

the last time a second coordinate was added in 2012. Then there were isolated reports of problems with the servers and technical equipment.
 

this year, However, scientists hope that the difficulties will not. "Since 1967 no problems because of it, no one there," reports the news Agency the words of Igor Blinov, head of the main metrological center of the State service of time and frequency.