Your body heat is under 95* fahrenheit.
Shivering
The umbles:
Get them out of wet clothing and the cold environment.
Move gently. Rewarm slowly. The body does not like sudden changes!
Food and drink if they can swallow on their own.
hypothermia wrap (giant human burrito)
Call for help, have them come to you.
be careful not to move too much if providing CPR, because they're at a high risk of ventricular fibrillation