Shivering is likely the first thing you'll notice as the temperature starts to drop because it's your body's automatic defense against cold temperature — an attempt to warm itself. Signs and symptoms of hypothermia include: 
Shivering
Slurred speech or mumbling
Slow, shallow breathing
Weak pulse
Clumsiness or lack of coordination
Drowsiness or very low energy
Confusion or memory loss
Loss of consciousness
Bright red, cold skin (in infants)
 Someone with hypothermia usually isn't aware of his or her condition because the symptoms often begin gradually. Also, the confused thinking associated with hypothermia prevents self-awareness. The confused thinking can also lead to risk-taking behavior.