An improved incubator and control apparatus include separate temperature and humidity control loops wherein a commanded temperature and a commanded relative humidity (RH) value are commanded to the control apparatus via a user interface. The control apparatus employs a humidifier rate saturation controller which acts responsive to both a humidity control signal and a current temperature to regulate the addition of humidity to the air within the incubator assembly to avoid a transient humidity from exceeding a predetermined value and thereby avoiding the generation of condensation within the incubator.