Potato tuber moth (Phthorimaea operculella), one of the leading potato-damaging pests in the world, has caused severe damage to potato production in South Korea after its introduction in the 1960s. This study surveyed the field occurrence of potato tuber moth in various sites in South Korea and used the results to validate the CLIMEX model, which spatiotemporally evaluated the potential distribution of potato tuber moths in response to climate change. The potato tuber moths were predicted to appear throughout the country, consistent with the results obtained for potato tuber moths in 96% of the field survey area. In addition, the climatic suitability of potato tuber moths will remain high due to climate change, suggesting a high risk for damage to seasonal potato production from seeding to harvesting. This spatiotemporal assessment of potato tuber moth distribution is expected to aid in establishing control strategies optimized based on time and place.