The 19th Session of the CLIVAR Scientific Steering Group (SSG-19) was held in La Paz, Mexico, between 11th and 14th June 2012. Dr Jim Hurrell and Professor Martin Visbeck, SSG co-chairs, led the meeting of 30 participants, comprised of SSG members, chairs or representatives of CLIVAR panels and working groups, representatives of the other core WCRP projects, and other invitees.