The most common sites of temperature measurement in clinical practice is through ears tympanic membrane ,but also its measure through the rectum, mouth, and axilla.

I discourage measuring temperature of the forehead as its inaccurate and affected by environment and sweat.

●Rectal : is generally considered the reference standard for measurement of core body temperature and is usually performed in infants . Rectal thermometry is contraindicated in patients with severe low white blood cell count or immune disease .

●Oral: generally is preferred in children who are old enough to cooperate,and also may be affected by recent ingestion of hot or cold liquids .

●Axillary: is consistently lower than rectal temperature, may be measured in patients who are unable to use an oral thermometer.

● infrared thermometry that is as Tympanic Membrane thermometers measure the amount of heat produced by the TM.

Infrared contact and non-contact forehead thermometers measure the amount of heat produced by the temporal arteries.

●Smart phones Apps that permit tracking of fever are available. They require an external sensor, with accuracy commensurate with that of the sensor. In the absence of adequate study, they cannot be recommended for use.

So in conclusion to make clinical descision especially infants it should be according to rectal temperature.

The mean normal temperature is generally considered to be 37°C (98.6°F)

Normal body temperature varies with age, time of the day, level of activity.

Normal temperature varies during the day

How to measure temperature ?