Body Temperature Chart – Normal, Fever & Hypothermia Ranges (°C & °F)
Last updated: February 28, 2026
A complete reference guide to human body temperature ranges across age groups. All values are shown in both Celsius (°C) and Fahrenheit (°F).
Normal Body Temperature
The widely cited "normal" body temperature of 37 °C (98.6 °F) comes from a study by German physician Carl Reinhold August Wunderlich in 1851, based on over one million readings from 25,000 patients. More recent research suggests the average has shifted slightly downward, with a 2020 Stanford University study finding a mean oral temperature closer to 36.6 °C (97.9 °F) in modern populations.
Normal body temperature is not a single fixed number. It fluctuates throughout the day — typically lowest in the early morning and highest in the late afternoon — and varies by measurement site, age, sex and physical activity.
Body Temperature Ranges by Category
| Category | Celsius | Fahrenheit |
|---|---|---|
| Severe hypothermia | < 28 °C | < 82.4 °F |
| Moderate hypothermia | 28–32 °C | 82.4–89.6 °F |
| Mild hypothermia | 32–35 °C | 89.6–95 °F |
| Below normal | 35–36.1 °C | 95–97 °F |
| Normal range | 36.1–37.2 °C | 97–99 °F |
| Low-grade fever | 37.3–38 °C | 99.1–100.4 °F |
| Moderate fever | 38.1–39.4 °C | 100.5–103 °F |
| High fever | 39.5–41 °C | 103.1–105.8 °F |
| Hyperpyrexia (emergency) | > 41 °C | > 105.8 °F |
Normal Ranges by Age Group
| Age Group | Normal Range (°C) | Normal Range (°F) |
|---|---|---|
| Newborns (0–3 months) | 36.5–37.5 °C | 97.7–99.5 °F |
| Infants (3–12 months) | 36.0–37.4 °C | 96.8–99.3 °F |
| Children (1–10 years) | 36.1–37.8 °C | 97.0–100.0 °F |
| Adults (11–65 years) | 36.1–37.2 °C | 97.0–99.0 °F |
| Older adults (> 65 years) | 35.8–36.9 °C | 96.4–98.4 °F |
Temperature by Measurement Method
Where you measure body temperature affects the reading. Rectal and ear (tympanic) measurements tend to read higher than oral, while axillary (armpit) readings tend to be lower.
| Method | Normal Average (°C) | Normal Average (°F) |
|---|---|---|
| Oral (mouth) | 36.8 °C | 98.2 °F |
| Rectal | 37.0 °C | 98.6 °F |
| Axillary (armpit) | 36.5 °C | 97.7 °F |
| Tympanic (ear) | 36.9 °C | 98.4 °F |
| Temporal (forehead) | 36.6 °C | 97.9 °F |
Fever Thresholds in Children
Pediatric fever thresholds differ from adults. The American Academy of Pediatrics and NHS guidelines consider the following temperatures as fever in children, depending on measurement method:
| Method | Fever Threshold (°C) | Fever Threshold (°F) |
|---|---|---|
| Rectal | 38.0 °C | 100.4 °F |
| Oral | 37.8 °C | 100.0 °F |
| Axillary | 37.2 °C | 99.0 °F |
| Tympanic | 38.0 °C | 100.4 °F |
For infants under 3 months, a rectal temperature of 38 °C (100.4 °F) or higher always requires prompt medical evaluation, regardless of other symptoms.
Factors That Affect Body Temperature
- Time of day: Temperature is lowest between 4:00–6:00 AM and peaks between 4:00–6:00 PM, with a typical variation of 0.5–1.0 °C (0.9–1.8 °F).
- Physical activity: Exercise can raise body temperature by 1–2 °C (1.8–3.6 °F) temporarily.
- Menstrual cycle: Women's basal body temperature rises by about 0.3–0.5 °C (0.5–0.9 °F) after ovulation due to progesterone.
- Age: Older adults have lower baseline temperatures and may not develop high fevers as readily.
- Ambient temperature: Extreme heat or cold can influence peripheral and core body temperature.
- Food and drink: Consuming hot or cold beverages before an oral reading can temporarily alter results.
When to Seek Medical Attention
- Adults: Fever above 39.4 °C (103 °F) or lasting more than 3 days
- Children: Fever above 38.9 °C (102 °F) with lethargy or irritability
- Infants under 3 months: Any fever at or above 38 °C (100.4 °F)
- Any age: Temperature above 41 °C (105.8 °F) — this is a medical emergency
- Hypothermia: Temperature below 35 °C (95 °F) — seek immediate medical help
Related Temperature Conversions
Data Accuracy
Temperature ranges on this page are based on published clinical guidelines from the American Academy of Pediatrics, NHS, and peer-reviewed medical literature. All Celsius-to-Fahrenheit conversions use the standard formula °F = °C × 9/5 + 32, consistent with the International Temperature Scale of 1990 (ITS-90).
About This Page
Content maintained by the CelsiusFahrenheit.co editorial team. All conversions follow the International Temperature Scale of 1990 (ITS-90) as defined by the Bureau International des Poids et Mesures (BIPM). Calculations use IEEE 754 double-precision arithmetic. Last reviewed: February 2026.