For most healthy adults, normal body temperature is usually somewhere between about 97 °F and 99 °F (roughly 36.1 °C to 37.2 °C), not a single exact number.

Typical “normal” range

  • The traditional “normal” is 98.6 °F (37 °C), but newer data show that a range is normal for most people.
  • Many medical sources describe normal adult temperature as roughly 97 °F to 99 °F (36.1 °C to 37.2 °C).
  • Normal oral temperatures often fall around 36.5–37.5 °C (97.7–99.5 °F).

Factors that change temperature

  • Temperature varies with age, time of day, activity level, hormones, and even the way you measure it (oral, rectal, ear, forehead, armpit).
  • Rectal readings tend to be a bit higher than oral, while armpit readings tend to be a bit lower.

When it may be a fever

  • Many clinicians treat a temperature of 100.4 °F (38 °C) or higher as a fever that may signal infection or illness.
  • Mildly elevated numbers just under that threshold can still be normal if you recently exercised, are overdressed, or it’s later in the day.

When it may be too low

  • Temperatures significantly below the usual range (for example, under about 95 °F / 35 °C) can indicate hypothermia, which is an emergency and needs prompt medical attention.
  • Older adults often naturally run a bit cooler, so even a “low-grade” temperature rise may represent a meaningful fever for them.

If your temperature is regularly outside the ranges above or you feel unwell (confusion, chest pain, trouble breathing, severe chills), seeking medical advice promptly is important.