Hypothermia is a dangerously low core body temperature—below 95°F (35°C). Common signs include uncontrollable shivering (which may stop in severe cases), confusion, drowsiness, pale or cold skin, slowed breathing or heart rate, and weakness or loss of coordination.
Because hypothermia gradually impairs thinking and movement, a person may not realize they need help. It is a medical emergency; call emergency services if these signs appear, especially confusion or trouble thinking clearly.
Source: Hypothermia — MedlinePlus Medical Encyclopedia (National Library of Medicine)