Acoustic temperature measurement at a remote location is provided. An acoustic source transmits acoustic radiation to an acoustic receiver along an acoustic path. The path passes through or near the remote location. The temperature is non-uniform along the path. A change in an integrated acoustic delay between the source and receiver along the path is measured. This acoustic delay can be either a phase velocity delay or a group velocity delay. The temperature at the remote location is determined by relating the measured change in integrated acoustic delay to the remote location temperature with a combined thermal-acoustic model. The combined model relates temperature to acoustic propagation velocity along the path. The combined model preferably includes temperatures of the source and receiver locations, and a heat source geometry at the remote location.