The invention relates to a method for deicing a rotor blade of a wind power plant, wherein a deicing procedure is started in the event of icing in an area of the rotor blade to be kept free of or to be freed from ice, in that an air flow is heated to a predetermined or predeterminable inflow temperature (10) and is guided from a blade root of the rotor blade through a channel or a channel system in the rotor blade into the area to be kept free of or to be freed from ice and subsequently entirely or partially back to the blade root, wherein the inflow temperature (10) and an outflow temperature (20) of the returned air flow are captured continuously or at certain time intervals. The invention further relates to a computer program, which prompts a control unit of a wind power plant to execute a corresponding method for deicing a rotor blade of a wind power plant, a deicing system of a wind power plant and a wind power plant. According to the invention, a temporal progression of at least one measurement signal c
