BACKGROUND: Injuries are affected by weather conditions, which influence various human activities. However, only a few studies have reported an association between injuries and weather conditions despite the fact that extreme weather conditions can occur more frequently with climate change. The goal of this study was to evaluate the association between outdoor temperature and traumatic and nontraumatic injury using emergency ambulance delivery. METHODS: We designed a prognostic study to evaluate the different effects of outdoor temperature depending on types of injury. Using a generalized additive model, we examined the association between outdoor temperatures and injuries in Korea from 2006 to 2008, adjusting for confounders such as relative humidity, day of the week, and long-term time trends. A random effects model was used to estimate combined effects across all areas. RESULTS: The city-combined effect estimate for nontraumatic injuries was 1.95% (95% confidence interval, 1.28-2.62%) corresponding to a 1 degrees C increase in mean temperature, whereas the relationship for traumatic injuries was not linear. The risk of nontraumatic injury related to temperature for males and elderly individuals was higher than for females and younger people. CONCLUSION: The risk of injury attributable to outdoor temperature was found to vary according to the injury type. This information may be useful for developing adaptation strategies related to climate change. LEVEL OF EVIDENCE: Prognostic study, level III.