Abstract: In a medical electronic thermometer system comprising a temperature sensing circuit for providing an analog signal representative of temperature being sensed, this temperature sensing circuit including a temperature transducer having a time lagged output; a voltage to rate converter responsive to the analog signal for providing uniform digital pulses at a repetition rate proportional to the temperature being sensed; and a digital decoder and display for displaying the temperature being sensed; an improved predictive circuit within the temperature sensing circuit for compensating for transducer lag and for enabling determination of ultimate temperature in advance of signal levels from the transducer indicative of such ultimate temperature, this predictive circuit generating a dual scale factor error curve.