A low body temperature indicates either exposure to cold weather or a decrease in the body's metabolic rate. It can also indicate both. Left unchecked, it may progress to hypothermia, a potentially life-threatening condition. According to Dictionary.com, hypothermia is an abnormal decrease in body temperature.
Although normal body temperature is 98.6 degrees Fahrenheit, according to WebMD, it can fluctuate depending on the part of the body used to measure temperature. For example, rectal temperature is higher than oral temperature, which is in turn higher than armpit temperature. Body temperature can also fluctuate according to the time of day. Some conditions and metabolic disorders, such as hypothyroidism, diabetes, shock or sepsis, can also lead to a fall in body temperature.