The normal human body temperature is around 37 °C (98.6 °F).
It however, does not have the same value for every person and varies according to the age of the individual. The normal body temperature value is also dependent on where and at what time it is measured. The body temperature is the highest around 6 pm in the evening and found to be the lowest at around 3 am in the morning.
The rectal (internal temperature) is usually higher than the skin temperature.
The body temperature is usually measured in the armpit area which is quite convenient but can also be calculated by inserting a thermometer in the rectum area or in vagina in case of women or even by ear and forehead thermometers.
It is quite essential to measure the body temperature to identify the presence of any disease that might have caused several changes to the body system. The persistence of disease can be monitored and effectiveness of a treatment can also be determined.