Climate variability brought about by the El Nino-Southern Oscillation has been linked to outbreaks of infectious diseases, such as hantavirus pulmonary syndrome, cholera, and malaria. Additionally, climate change affects the distribution of diseases, causing some regions to become more or less favorable for the transmission of certain pathogens. Mosquitoes in particular are sensitive to climate change, and mosquito-borne diseases may become more common at higher latitudes and elevations under warmer conditions. This study examined the potential changes in dengue risk in Hawaii, USA, in response to climate variability and change using GIS. Dengue, transmitted by mosquitoes of the genus Aedes, is considered to be an emerging disease and almost half of the world's population is at risk of infection. Previous research has identified mosquito habitat and potential dengue risk areas in Hawaii based on average climate conditions, and this study incorporated notions of climate variability and change to that model and determined the population at risk under different scenarios. Dengue risk areas generally contract during El Nino-induced droughts and expand as a result of increased precipitation received during La Nina events. Future climate scenarios predict warmer temperatures and wetter summers in Hawaii over the next 25 yr, which will cause an expansion of mosquito habitat and potential dengue risk areas. The results of this study contribute to the overall understanding of climate-dengue relationships and will aid public health officials in efforts to determine where to concentrate resources for mosquito and dengue surveillance, given certain current or forecast climate conditions.