An increase in body temperature is one of the first signs of an infection or an illness in humans. The average body temperature for infants range from 97 to 100 degrees Fahrenheit or 38 degrees Celsius, and anything above that is generally considered a fever.Children and infants with a fever need to be watched and comforted with lukewarm baths or sponge baths.he normal body temperatures for children are the same as an adult human and are considered to be between 36 to 36.8 degrees Celsius or 96.8 to 98.2 degrees Fahrenheit.