1. How to judge whether a six-month-old baby has a fever? 1.1 Method of measuring body temperature 1.2 Normal body temperature range When determining whether a baby has a fever, the most common method is to measure the body temperature. For babies who are six months old, you can use an ear thermometer or forehead thermometer to measure the temperature. Under normal circumstances, the body temperature of a six-month-old baby should be between 36.5°C and 37.5°C. What should I do if my baby is 2 or 6 months old and has a fever?