Decreased UV radiation is associated with augmented depression, drug use, and domestic violence. Findings entailing folic acid suggest that gender moderates such relationships. The present study was designed to evaluate the relationship between UV radiation and Neuroticism among females and males. Representative consumer panels of three Peruvian cities at decreasing levels of radiation exposure were compared. A 7-item Neuroticism scale was used. A hierarchical regression model revealed that Neuroticism increases with decreased exposure to UV radiation, but the expected radiation x gender interaction failed to materialize. The findings uphold the concept that Neuroticism is responsive to geophysical stimulation. Improvements of mental health can be expected with climate change. The study should be replicated with strengthened methodology.