You just brought your bundle of joy home, and like many new parents, you may be wondering what is a normal body temperature for an infant. Temperature regulation is different for infants than adults. We’re here to help you understand how babies regulate their temperature and what it means for caring for your newborn.
Rectal reading: A reading of 98.6° F (37° C) is just the average rectal temp. A normal low can be 96.8° F (36° C) in the morning. It can change to a high of 100.3° F (37.9° C) late in the day.
Mouth reading: A reading of 97.6° F (36.5° C) is just the average mouth temp. A normal low can be 95.8° F (35.5° C) in the morning. It can change to a high of 99.9° F (37.7° C) late in the day.
We strongly recommend rectal temperatures when checking a baby as these are the most accurate and will give your pediatrician a better idea on how to proceed.
If your newborn has a fever temperature of 100.4° F (38° C) or above, it's important to seek medical attention. Fevers can be a sign of an underlying illness in infants and it's best to talk to a doctor to determine what's normal for your baby. Summer Health can connect you to a pediatrician in 15 minutes to help answer your questions and figure out the right next care steps for your little one.
Babies have a hard time regulating their temperature because their bodies are still developing and they have a larger body surface area relative to their mass, compared to adults. This means that they lose heat faster and have a harder time retaining heat, making it easier for their body temperature to fluctuate.
Additionally, newborns do not have fully developed systems for regulating their body temperature, such as sweating, which helps to cool the body down. These factors combined make it more difficult for newborns to regulate their temperature, which is why they can easily become too hot or too cold.
If you notice your baby acting differently or appearing “off”, such as more sluggish, more sleepy, not feeding well, or not acting at their baseline, consider checking their temperature via touch and thermometer. If you don’t have a thermometer, when checking younger babies you can use touch by checking the back of their neck for warmth. If they feel warm and sweaty on the back of their neck, it is best to consult a pediatrician.
If you are looking for baby thermometers to keep track of your little’s temperature, look no further.
Fevers can be an alarming and confusing ordeal for parents and caregivers. Every baby's needs will be unique, however there are simple steps you can take at home to regulate your newborn’s temperature to have peace of mind. If you have questions about your baby’s temperature or fever, do not hesitate to reach out to Summer Health. We can connect you to licensed pediatricians to answer your questions over text in 15 minutes, 24/7.
Medically Reviewed By
Dr. Alisa Roysman
Touro University College of Osteopathic Medicine
February 25, 2023