A low-grade fever for adults and children is when your body temperature is slightly elevated above normal. This is generally between 98.8°F (37.1°C) and 100.6°F (38.1°C). ... For adults, this is an oral temperature of 103°F (39.4°C). For children over 3 months old, this is a rectal temperature of 102°F (38.9°F) or higher.Apr 12, 2018
