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, 07 July 2025
 

 

                                              Bulletin C 70
 

                                              To authorities responsible
                                              for the measurement and
                                              distribution of time
 

 

 

                          INFORMATION ON UTC - TAI
 

 

 NO leap second will be introduced at the end of December 2025.
 The difference between Coordinated Universal Time UTC and the
 International Atomic Time TAI is :
 

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

 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
                                            Director
                                            Earth Orientation Center of IERS
					    Observatoire de Paris, France