The range expansion of organisms towards higher latitudes and altitudes is often limited by colder temperatures and the shorter growth season. In parasites, survival outside the host is most likely to affect their potential establishment in novel environments. We conducted a large scale transplant experiment to predict the potential spread of the deer ked Lipoptena cervi (Diptera: Hippoboscidae), a blood-feeding ectoparasite of boreal cervids. We studied the off-host survival and pupal development of deer ked in five sites along a latitudinal gradient reaching from its current range in central Finland to northernmost Fennoscandia. We showed that the deer ked is able to survive and complete its development even in arctic environments, 500 km northwards beyond the current range. Performance deteriorated steadily towards north, where lower summer temperatures prolonged the developmental period and shortened the suitable host search time by several weeks. The relevance of the experiments for estimating the spread of deer ked to the north is discussed.