Global climate change impacts on aquifer thermal regime in the Sendai plain, Japan were estimated by incorporating three scenarios from MRI Global Climate Model (GCM). Statistical downscaling technique was used to link the coarse resolution GCM output with the corresponding local scale climatic parameters. The magnitude of ground surface warming as evaluated from the observed Temperature-Depth (T-D) profiles in 14 sub-wells at 5 locations ranges 0.9–1.3°C. The annual averaged downscaled temperature was estimated to be increased by 2.3–3.4°C. Projected annual precipitation would increase by 3–129 mm (0.2–11% from 1968–2007 periods). The overall results show that the groundwater temperature, under the changed ground surface temperature and precipitation, will increase in a range of 1.7–3.0°C. The estimated figures suggest that the climate change impacts will be critical for maintaining or achieving the ecological balance of ecosystems, which will inform decision makers for taking appropriate mitigation measures.