A body temperature below 97.3°F (36.3°C) is generally considered low, though “normal” is more of a range than a single number. The old standard of 98.6°F dates back to 1868, and Stanford Medicine researchers have found that today’s average body temperature is closer to 97.9°F, with healthy adults falling anywhere between 97.3°F and 98.2°F. So a reading of 97.5°F is perfectly normal for many people, while a reading below 95°F (35°C) enters the territory of hypothermia and needs medical attention.
What matters most is context: when you took your temperature, how you measured it, your age, and whether you have other symptoms. A slightly low reading on its own is rarely cause for alarm, but a persistently low temperature or one paired with other signs can point to something worth investigating.
Normal Temperature Is a Range, Not a Number
Your body temperature fluctuates throughout the day following a built-in rhythm tied to your internal clock. It typically hits its lowest point in the early morning hours and peaks around 6 p.m., with a swing of up to 1.5°F between the high and the low. This means a reading of 97.2°F at 5 a.m. could be completely normal for you, even though the same number at 4 p.m. might be unusually low.
Beyond daily rhythms, your baseline temperature is personal. Research on more than 18,600 people found that average body temperature decreases with age, with roughly a 0.3°F difference between the oldest and youngest groups. People over 60 were significantly more likely to have temperatures below 96°F compared to younger adults. Women tend to run slightly warmer than men during certain phases of their menstrual cycle. Even your fitness level, body size, and overall health can shift your personal baseline up or down.
Where You Measure Matters
The thermometer you use and where you place it can easily account for a “low” reading. Oral temperatures average about 1.1°F lower than rectal temperatures, and the gap can be as large as nearly 3°F in some cases. Forehead and ear thermometers are convenient but less precise, sometimes reading more than 1.5°F lower than a rectal measurement. If you took your temperature under your arm (axillary), that method typically reads about 1°F lower than oral.
If your reading seems surprisingly low, try measuring again after keeping your mouth closed for a few minutes, avoiding cold drinks beforehand. A single low reading from a forehead scan isn’t particularly meaningful on its own.
Common Reasons for a Low Temperature
Several everyday and medical factors can push your temperature down. Here are the most common:
- Cold exposure: The most obvious cause. Being in a cold environment, wearing wet clothing, or spending extended time outdoors in winter can drop your core temperature faster than your body can compensate.
- Underactive thyroid: Thyroid hormones are essential for heat production. They drive thermogenesis in brown fat, muscle tissue, and other organs. When your thyroid isn’t producing enough hormone, your body’s internal furnace runs low, and a persistently cool temperature is one of the hallmark signs, often alongside fatigue, weight gain, and dry skin.
- Low blood sugar: Hypoglycemia reliably lowers body temperature by roughly 0.3°C to 0.4°C (about half a degree Fahrenheit). Your body needs fuel to generate heat, and when blood sugar drops, heat production slows. This is relevant for people with diabetes who take insulin, but it can also happen after prolonged fasting or intense exercise without eating.
- Older age: As people age, the body becomes less efficient at regulating temperature. The ability to shiver decreases, blood vessels don’t constrict as effectively, and there’s often less insulating body fat. A study found that temperatures below 96°F become increasingly common after age 60.
- Fatigue and sleep deprivation: Your body drops its temperature naturally during sleep, and chronic exhaustion can blunt your thermoregulatory response during waking hours too.
Medications That Affect Body Temperature
Certain medications interfere with how your body regulates heat. Beta-blockers, commonly prescribed for high blood pressure and heart conditions, reduce blood flow to the skin by altering how your cardiovascular system responds to temperature demands. Antipsychotic medications and drugs with strong anticholinergic properties (which block certain nerve signals) can impair sweating and disrupt the body’s thermostat in both directions. People taking medications for Parkinson’s disease may also experience altered temperature regulation.
If you’re on any of these medications and consistently notice low readings, it’s worth mentioning to whoever prescribed them. The effect is usually mild, but in combination with cold weather or other risk factors, it can become significant.
When a Low Temperature Signals Something Serious
Most people assume that infection causes fever, but about 20% of patients with sepsis (a dangerous, body-wide response to infection) actually present with a low temperature rather than a high one. In medical settings, a temperature below 96.8°F (36°C) in someone with signs of infection is taken seriously. Hypothermic sepsis patients tend to have worse outcomes than those who develop fever, likely because the low temperature reflects a weakened immune response rather than a body fighting back effectively.
Other warning signs that a low temperature may indicate a medical emergency include confusion or slurred speech, drowsiness or unusual lethargy, shallow breathing, a weak pulse, or poor coordination. These symptoms together suggest your core temperature has dropped into a range where organs start to struggle.
Hypothermia is classified in three stages. Mild hypothermia (90°F to 95°F) causes intense shivering, clumsiness, and difficulty thinking clearly. Moderate hypothermia (82°F to 90°F) is where shivering may actually stop, which is a dangerous sign because it means the body has lost its primary warming mechanism. Severe hypothermia (below 82°F) can cause unconsciousness and is life-threatening.
Low Temperature in Babies and Young Children
Infants are especially vulnerable to low body temperature because they have a large surface area relative to their body weight, limited fat stores, and an immature ability to shiver. According to the CDC, babies with hypothermia display bright red, cold skin and very low energy. Unlike adults, who shiver and complain of cold, a hypothermic baby may simply become unusually quiet and limp.
Newborns in particular lose heat rapidly. A rectal temperature below 97.7°F (36.5°C) in a newborn is considered low and worth addressing, even if the baby otherwise looks fine. Keeping the room warm, using skin-to-skin contact, and dressing the baby in layers are all practical steps, but a persistently low reading in an infant always warrants a call to your pediatrician, because in very young babies, low temperature can be the only visible sign of infection.
What to Do About a Low Reading
If you took your temperature and it came back low but you feel fine, the most likely explanation is normal variation, measurement error, or the time of day. Try measuring again with a reliable thermometer (digital oral or rectal thermometers are more accurate than forehead scanners) and see if the reading is consistent.
If your temperature is consistently below 97°F across multiple readings taken at different times of day, and especially if you also experience fatigue, unexplained weight changes, dry skin, or sensitivity to cold, a thyroid panel blood test is a reasonable next step. Hypothyroidism is common, affecting roughly 5% of adults, and is easily treatable.
If your temperature drops below 95°F and you’re experiencing confusion, excessive shivering, or drowsiness, that’s a medical emergency. Move to a warm environment, remove any wet clothing, cover yourself with blankets, and seek help. Avoid direct heat sources like heating pads on bare skin, which can cause burns when your body’s sensation is dulled by cold. Warm, sweet drinks help if you’re alert enough to swallow safely.