What is the normal axillary (underarm) body temperature?

Body temperature is the result of metabolic processes converting chemical energy into thermal energy. It fluctuates naturally due to factors such as sex, age, circadian rhythm, physical activity, and emotional state—yet these variations typically remain within the normal physiological range. So, what constitutes a normal axillary (underarm) temperature? The following section addresses this question.

What Is Considered a Normal Axillary Temperature?

Under typical conditions, a normal axillary temperature ranges from 36.0°C to 37.0°C. Individual variations in constitution mean that baseline axillary temperatures may differ among people. Moreover, normal physiological fluctuations occur due to multiple factors—including age, time of day, and sex. To measure axillary temperature accurately, first shake a mercury thermometer down to below 36°C, then place it firmly in the armpit. After waiting 5–10 minutes, read the value. The standard normal range for axillary temperature is 36°C–37°C. A reading between 37.4°C and 38°C indicates low-grade fever; 38°C–39°C signifies moderate fever; and 39°C–41°C reflects high fever. Therefore, individuals experiencing fever should seek medical evaluation based on their specific symptoms and clinical context.

Knowledge Extension: How to Read a Thermometer

1. Mercury Thermometer

Mercury thermometers are calibrated from 35°C to 42°C. The scale comprises 14 major divisions, each representing 0.5°C; each major division is further subdivided into five minor divisions, with each minor division corresponding to 0.1°C. When reading the thermometer, align your line of sight horizontally with the upper surface of the mercury column. Hold the thermometer by its non-mercury end, keeping it level and horizontal. Gently rotate it while observing until the mercury column becomes clearly visible.

2. Infrared Thermometer

An infrared thermometer measures body temperature using radiative principles. Its infrared sensor detects only the infrared radiation emitted by the human body and emits no radiation itself. This non-contact method enables rapid, convenient temperature assessment, with readings displayed directly on-screen. In contrast, digital electronic thermometers emit an audible “beep” signal upon completion of measurement; simply remove the device and view the temperature reading on its display screen.

The above outlines what constitutes a normal axillary temperature. We hope this information proves helpful to you.