Your body temperature is the measure of your internal heat, typically around 98.6°F (37°C) when healthy. This baseline reflects your body's balance between heat production and loss.
Your hypothalamus acts as the thermostat, regulating temperature through processes like sweating, shivering, and blood vessel constriction. Core temperature (measured rectally) is more accurate than oral readings, which can vary by 0.5-1°F (0.3-0.6°C).
| Method | Normal Range (°F) | Notes |
|---|---|---|
| Oral | 97.5-98.9 | Most common but affected by breathing/mouth position |
| Rectal | 98.6-99.9 | Most accurate for core temperature |
| Armpit | 95.8-98.2 | Least accurate; often 1°F lower than oral |
| Ear | 96.4-99.1 | Measures tympanic membrane temperature |
Many assume 98.6°F is universal, but normal ranges vary by individual, time of day, and activity level. Morning temperatures average 0.5-1°F lower than evening readings. Women also experience slight fluctuations during menstrual cycles.
I once measured my temperature hourly for a week and found mine varied by 1.2°F between morning and evening. This reinforced how personal baselines matter-what's "normal" differs for everyone.
Consult a doctor if your temperature exceeds 103°F (39.4°C) or falls below 97°F (36.1°C) without explanation. Persistent low-grade fevers (99-100°F/37.2-37.8°C) also warrant evaluation.