Abstract: White-fleshed nectarines have gained popularity in recent years but there is limited information on their adaptability. Thus, the objective of this trial was to investigate growing degree-days (GDD; base temperature of 4.4 ^oC), full bloom and harvest dates, fruit quality, and yield of five white-fleshed nectarines [(Prunus persica var. nectarine)] under conditions of southwest Idaho in the Intermountain Region of the United States during 2003-07. The average response analyses over these years indicated that ‘Arctic Jay’ and ‘Arctic Pride’ bloomed earlier, while ‘Arctic Mist’ bloomed later than other cultivars. Arctic Jay was the earliest and Arctic Snow was the latest cultivar to harvest and needed 136 days and 181 days between full bloom and harvest, respectively. On average, ‘Arctic Pride’, ‘Arctic Mist’, and ‘Arctic Snow’ were harvested after the second half of September, and the periods between bloom and harvest for these cultivars were 166, 180, and 181 days, respectively. The difference between the earliest and latest cultivar for full bloom dates was only 2 days or 14 ^oC GDD, while the range for harvest dates was 16 days or 608.2 ^oC GDD. ‘Arctic Jay’ had excellent fruit quality attributers and on average, was harvested on 21 August. ‘Arctic Pride’ had moderately large fruit size and high SSC and extremely attractive skin and flesh color, but had moderately low yield. Considering all factors evaluated in this project, ‘Arctic Jay’, ‘Arctic Queen’, and ‘Arctic Pride’ were suitable choices for early, mid, and late season cultivars, respectively. ‘Arctic Mist’ could have some potential for planting in this study. The growing season was not sufficient to mature ‘Arctic Snow’ and thus not recommended for the region.