An experimental study was performed to characterize local and average heat transfer coefficients on a horizontal disk impinged by a circular liquid jet. The radial distribution of local heat flux and surface temperature were determined under unsteady-state conditions. The inverse heat conduction problem was solved using the responses of sensors located inside the experimental disk. It was shown that the distribution of the surface heat flux and the surface temperature was dependent on the radial location and the time. The average Nusselt number was seen to be independent of the nozzle-to-heat exchange surface spacing. It increased with the Reynolds number and the nozzle diameter.