Normal body temperature varies by person, age, activity, and time of day. The average normal body temperature is generally accepted as 98.6°F (37°C). Some studies have shown that the "normal" body temperature can have a wide range, from 97°F (36.1°C) to 99°F (37.2°C).
A temperature over 100.4°F (38°C) most often means you have a fever caused by an infection or illness.
Body temperature normally changes throughout the day.
Normal body temperature; Temperature - normal
Sajadi MM, Mackowiak PA. Temperature regulation and the pathogenesis of fever. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 8th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 55.
Sullivan JE, Farrar HC, Section on Clinical Pharmacology and Therapeutics, Committee on Drugs. Fever and antipyretic use in children. Pediatrics. 2011;127:580-587.
Update Date 1/31/2015
Updated by: Linda J. Vorvick, MD, medical director and director of didactic curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.