What is a normal temperature?

Normal body temperature is a range, not a sacred number: 97.7F to 99.1F (36.5C to 37.3C) for the average healthy adult, with the classic 98.6F (37C) as the midpoint, per MedlinePlus's vital-signs table. The number moves for normal reasons: your temperature runs lower in the early morning and higher in late afternoon and evening (a full degree of daily swing is ordinary), rises after exercise, hot drinks, and warm rooms, varies by measurement site (ear and forehead read differently from mouth), and shifts with the menstrual cycle. A fever is generally 100.4F (38C) and up - and what the fever means matters more than the degree: most fevers are your immune system working and pass in two to three days. The thresholds for action, from MedlinePlus's fever guidance: adults should call a doctor for fever holding or climbing past 103F (39.4C), any fever past 48 to 72 hours, or fevers recurring for a week or more; fever with confusion, stiff neck, breathing trouble, or seizure is an emergency; and a baby under 3 months at 100.4F is a same-day problem, always. Low readings count too: below 95F (35C) is hypothermia territory and an emergency. Measurement tip: use the same method each time when tracking - comparisons across different thermometers mislead. Pymander is a free AI doctor, 24/7 by text, that can help you read a temperature in context.