tempature gage keeps lowering on 1997 Hyundai Tiburon

my tibby doesnt over heat air stays warm but when i drive the temp gage lowers back to cold again the air doesnt change stays warm im not sure if the gage is going or its the thermostat or is it because its been below freezing here for the last 5 weeks?

Asked by for the 1997 Hyundai Tiburon
Check where the temp sense cable screws onto the engine block. It may be loose. Had the problem on mine