INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS)


SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE


SERVICE DE LA ROTATION TERRESTRE DE L'IERS
OBSERVATOIRE DE PARIS
61, Av. de l'Observatoire 75014 PARIS (France)
Tel.      : +33 1 40 51 23 35
e-mail    : services.iers@obspm.fr
http://hpiers.obspm.fr/eop-pc




Paris, 6 July 2016


Bulletin C 52


To authorities responsible for the measurement and distribution of time




UTC TIME STEP
on the 1st of January 2017




A positive leap second will be introduced at the end of December 2016.
The sequence of dates of the UTC second markers will be:


2016 December 31, 23h 59m 59s
2016 December 31, 23h 59m 60s
2017 January   1,  0h  0m  0s


The difference between UTC and the International Atomic Time TAI is:


from 2015 July 1, 0h UTC, to 2017 January 1 0h UTC   : UTC-TAI = - 36s
from 2017 January 1, 0h UTC, until further notice    : UTC-TAI = - 37s






Leap seconds can be introduced in UTC at the end of the months of December
or June, depending on the evolution of UT1-TAI. Bulletin C is mailed every
six months, either to announce a time step in UTC or to confirm that there
will be no time step at the next possible date.




Christian Bizouard
Head
Earth Orientation Center of IERS
Observatoire de Paris, France