The American Academy of Pediatrics (AAP) says that the normal body temperature for a healthy baby is between 36degC to 38degC. A fever would be any temperature that rises to 38degC or above. If you are indeed worried, look out for other symptoms like vomiting, loss of appetite, earaches and general fussiness. Best to bring baby to the doctor then.
http://www.parents.com/baby/care/american-baby-how-tos/treat-babys-first-fever/
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