What temperature is considered a fever in adults?

A fever in adults is typically defined as having a body temperature greater than 37 degrees Celsius (98.6 degrees Fahrenheit). This threshold indicates that the body is responding to an infection, inflammation, or other illness. A sustained change above this normal temperature indicates a physiological response that triggers various immune responses as the body attempts to fight off what may be causing the elevation in temperature.

While normal body temperature can vary slightly between individuals and at different times of the day, anything consistently above 37 degrees Celsius is sufficient for a clinical diagnosis of fever. It is important to note that lower thresholds, such as 37 degrees Celsius, would be considered normal, and temperatures less than this would certainly fall under normothermic conditions.

The threshold of greater than 39 degrees Celsius is often used in clinical settings to denote a high fever, which may warrant more immediate evaluation, but the fundamental distinction for a simple fever begins at the higher edge of normal, which is why the correct choice is that a fever begins at temperatures greater than 37 degrees Celsius.