What temperature in Celsius is considered a fever?

A body temperature of 38 degrees Celsius is widely recognized as the threshold for fever in adults. Normal body temperature is generally around 36.1 to 37.2 degrees Celsius. When a person's temperature rises to 38 degrees or above, it indicates an immune response, often due to infection or illness. This increase in temperature serves as a defensive mechanism, helping the body to fight off pathogens.

While 37.5 degrees Celsius may represent a mild elevation, it does not meet the clinical definition of fever. Higher temperatures, such as 39 degrees or 40 degrees Celsius, represent more significant fever or hyperthermia and may indicate a more severe condition requiring medical attention. Thus, while elevated temperatures signal a possible underlying issue, the recognized threshold for fever begins at 38 degrees Celsius.