According to the search results, a low-grade fever in babies is usually described as a rectal, ear, or forehead temperature between 100°-102°F (37.8°- 39°C) . Some people may consider anything between 98.6 degrees and 100.3 degrees a mild fever, while others may think temperatures between 99.5 degrees and 102.2 degrees indicate a mild fever. However, among most doctors, a mild or low-grade fever in babies is between 100 and 102 degrees. Unless the babys behavior has changed or there are other concerning symptoms, no treatment may be necessary for a low-grade fever. Its important to note that fever in newborns may be due to infection, and a rectal temperature of 100.4 degrees or higher in a baby younger than 2 months old requires an urgent evaluation by a doctor. Parents should call the doctor if their 3-6 month old has a temperature of 101 or greater, and with babies and children older than 6 months, they may need to call if the temperature is greater than 103, but more than likely, associated symptoms will prompt a call.