A direct drive wind turbine with a thermal control system has a generator with a rotor and a stator and a bearing with an inner ring and an outer ring connecting the rotor and the stator rotatively. The thermal control system includes a cooling system and a heating system. The cooling system includes at least one heat sink which is in thermal communication with the inner ring of the bearing and a heat dissipater which is in thermal communication with the heat sink. The heating system includes at least one heating element being in thermal communication with the outer ring of the bearing.