Our study conducted spatial analysis to examine how temperature and other environmental factors might affect dengue fever distributions, and to forecast areas with potential risk for dengue fever endemics with predicted climatic change in Taiwan. Geographic information system (GIS) was used to demonstrate the spatial patterns of all studied variables across 356 townships. Relationships between cumulative incidence of dengue fever, climatic and non-climatic factors were explored. Numbers of months with average temperature higher than 18 °C per year and degree of urbanization were found to be associated with increasing risk of dengue fever incidence at township level. With every 1 °C increase of monthly average temperature, the total population at risk for dengue fever transmission would increase by 1.95 times (from 3,966,173 to 7,748,267). A highly-suggested warmer trend, with a statistical model, across the Taiwan Island is predicted to result in a sizable increase in population and geographical areas at higher risk for dengue fever epidemics.