Excluding exposure to cold and hypothermia, there are several conditions that can cause low body temperature such as hypothyroidism, diabetes and shock, states WebMD. Alcohol or drug use, infections in newborns or the elderly, and life-threatening infections such as sepsis may also cause a lower-than-normal body temperature.
Inaccuracies in thermometers and human error can also give a false temperature, notes WebMD. Common causes include not leaving the thermometer in place long enough or taking an oral temperature within 20 minutes of drinking a cold beverage. Not keeping the mouth closed around the thermometer, a weak battery and not putting the thermometer in the correct place can also cause inaccurate temperature readings.
Normal body temperature is 98.6 degrees Fahrenheit, according to Mayo Clinic. Hypothermia begins when a person's body temperature is 95 degrees or less. Hypothermia occurs as a person's body loses heat faster than it can produce heat. This can happen indoors as well as out. Air conditioning that is too cold for infants or elderly people can cause a drop in body temperature. Other situations that may cause hypothermia include wearing clothes unsuited for cold weather, inadequate heating in the home and staying in the cold for too long.