A chemical mechanical polishing apparatus includes a rotatable platen to hold a polishing pad, a rotatable carrier to hold a substrate against a polishing surface of the polishing pad during a polishing process, a polishing liquid supply port to supply a polishing liquid to the polishing surface, a thermal control system including a movable nozzle to spray a medium onto the polishing surface to adjust a temperature of a zone on the polishing surface, an actuator to move the nozzle radially relative to an axis of rotation of the platen, and a controller configured to coordinate dispensing of the medium from the nozzle with motion of the nozzle across the polishing surface.