Hi, Just received from IERS: ------------------------------------------------------------------------------ INTERNATIONAL EARTH ROTATION AND REFERENCE SYSTEMS SERVICE (IERS) SERVICE INTERNATIONAL DE LA ROTATION TERRESTRE ET DES SYSTEMES DE REFERENCE SERVICE DE LA ROTATION TERRESTRE OBSERVATOIRE DE PARIS 61, Av. de l'Observatoire 75014 PARIS (France) Tel. : 33 (0) 1 40 51 22 26 FAX : 33 (0) 1 40 51 22 91 e-mail : services.iers@obspm.fr http://hpiers.obspm.fr/eop-pc Paris, 5 January 2012 Bulletin C 43 To authorities responsible for the measurement and distribution of time UTC TIME STEP on the 1st of July 2012 A positive leap second will be introduced at the end of June 2012. The sequence of dates of the UTC second markers will be: 2012 June 30, 23h 59m 59s 2012 June 30, 23h 59m 60s 2012 July 1, 0h 0m 0s The difference between UTC and the International Atomic Time TAI is: from 2009 January 1, 0h UTC, to 2012 July 1 0h UTC : UTC-TAI = - 34s from 2012 July 1, 0h UTC, until further notice : UTC-TAI = - 35s 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. Daniel GAMBIS Head Earth Orientation Center of IERS Observatoire de Paris, France