Normal body temperature for a baby is 98.6 degrees Fahrenheit (the way we measure outside weather temperatures). If the temperature is measure correctly with the tip of the thermometer in the armpit, the baby's temperature shouldn't be different by more than 1 degree in either direction (97.6 - 99.6). Babies are more easily affected by both cold and heat, so it is important to dress your baby correctly for the temperature of the house/building and the outside weather.