Persian or English walnut (Juglans regia L.), the walnut species cultivated for nut production, is one of the oldest food sources known and is grown worldwide in temperate areas. In this work, historical data have been collected thanks to the team of the late Eric Germain, former head of breeding program at INRAE of Bordeaux from 1977 to 2007 and current data have been collected in the two French walnut experimental stations of Creysse and SENuRA. These data have been processed in order to assess the phenotypic variation among 150 accessions of the 259 accessions of the INRAE's Walnut Genetic Resources. Phenotypical data have been collected for a period from 1965 to 2016, with a majority of data between 1989 and 2016. All accessions are grafted trees mostly located in the arboriculture experimental unit in Toulenne (latitude 44°34’37.442’’N – longitude 0°16’51.48’’O), near Bordeaux (France). For some accessions, several data have been also available from the two French walnut experimental stations of Creysse (latitude 44°53’16.529’’N – longitude 1°36’23.838’’E) and SENuRA (latitude 45°8’38.565’’N – longitude 5°17’34.323’’E). The dataset consists in the raw phenotypic datafile and the three climate datafiles of the three sites of Toulenne, Creysse and SENuRA, all in "tab" format.