Fever Guidelines for Babies Under 2 Months

Important information:

A baby younger than 2 months has an immune system that is still developing. This makes them more likely than older children to get sick from viruses and bacteria. Sometimes the only sign of illness in a young baby is a temperature that is too high or too low.

Normal temperature range:

Too low: 97.5 °F (36.4 °C) or below

Normal: 97.7 °F (36.5 °C) to 100.3 °F (37.9 °C)

Too high: 100.4 °F (38.0 °C) or above

Instructions for taking your baby’s temperature:

Check your baby’s temperature if they have any of these signs:

  • Cold symptoms

  • Cough

  • Rash

  • Not feeding well

  • Crying and hard to calm

  • Acting differently than usual

  • Feeling warm (babies can have a fever even if they do not feel hot)

How to Take a Temperature

  • For babies under 2 years, a rectal temperature is the most accurate.

  • Temperatures taken by mouth, under the arm, on the forehead, or in the ear are not accurate for this age.

If the Temperature Is Too High or Too Low

  • Do not give acetaminophen (Tylenol®) or any fever medicine.

  • Check your baby’s clothing. Too many layers or blankets can raise body temperature.

    • Remove extra clothing or blankets.

    • Recheck the temperature.

  • If your baby’s temperature stays too high or too low, call your child’s healthcare provider right away. They may ask you to bring your baby to the Children’s Hospital of Philadelphia (CHOP) Emergency Department.

 

Reviewed March 2026 by Lori Worthy, CRNP