The average body temperature, taken with a thermometer in the mouth, is 37ºC (98.6ºF), but anywhere between 36.5ºC and 37.2ºC (97.7ºF and 99ºF) can be considered normal. Armpit temperatures are 0.2ºC to 0.3ºC lower than this. A fever is a temperature reading of 37.5ºC (99.5ºF) or above.