Seasonal hindcasts are performed by Norwegian Climate Prediction Model (NorCPM, Counillon et al. 2014). The hindcasts start on the 15th of January, April, July and October each year during 1985–2010. Totally, there are 104 hindcasts (26 years and 4 season starts per year). Each hindcast consists of 9 realisations (ensemble members) and is 13 months long. The hindcasts are forced by CMIP5 historical forcings (Taylor et al. 2012) before 2005 and the representative Concentration Pathway 8.5 (RCP8.5, van Vuuren et al. 2011) forcings after 2005. Initial conditions are taken from the first 9 out of the 30 ensemble members of the NorCPM_V1 reanalysis (DOI HERE).