Introduction A fever is a temporary rise in body temperature, usually as a response to infection, inflammation, or other medical conditions. While commonly associated with illness, not all temperature elevations indicate a serious problem. Understanding normal body temperature ranges by age and what constitutes a fever is essential for proper monitoring and timely medical care. Body temperature can vary by age, time of day, activity level, and measurement method (oral, rectal, ear, forehead, or axillary). Normal Body Temperature Ranges by Age Age Group Normal Body Temperature Newborns (0–3 months) 97.9–100.4°F (36.6–38°C) Infants (3–12 months) 99–100.4°F (37.2–38°C) Toddlers (1–3 years) 98.6–100.4°F…