Fever is the body's normal response to infection and other conditions, both minor and serious. Most fevers help the body fight infection.

The average normal body temperature is 98.6 A?F (37 A?C) orally. It can change during the day from a low of 97.4 A?F (36.3 A?C) in the morning to a high of 99.6 A?F (37.6 A?C) in the late afternoon. Mild elevations—(99.8 A?F (37.7 A?C)— can be caused by too much clothing, a hot bath, or hot weather.

Fever in a child is present when a child's temperature is 100.4 A?F (38 A?C) or higher measured rectally.