You may feel ill and take your temperature assuming you have a fever. Instead, your thermometer reads 96°F (35.55°C). This lower-than-average temperature could occur for several reasons. You may have an illness that corresponds to low temperatures. You may have taken your temperature incorrectly. Age may play a factor. Finally, you may have a health condition causing the lower body temperature.

Understanding body temperature is important to making sense of your 96-degree reading. Long ago, doctors considered 98.6°F (37°C) to be a “normal” temperature. That has changed in recent years. A normal temperature is now considered to be a bit lower than that, and it depends on your age and the method you use to measure your temperature.

One 2019 research review looked at 36 prior studies about body temperature and found that adults less than 60 years old had a average temperature of 98.04°F (36.68°C). Adults more than 60 years old had a average temperature of 97.7°F (36.5°C).

The study also examined body temperatures taken with different methods. These average temperatures by method were:

  • Rectal: 98.67°F (37.03°C)
  • Eardrum: 97.95°F (36.63°C)
  • Oral: 97.83°F (36.57°C)
  • Armpit: 96.75°F (35.97°C)

Average temperatures for newborns and children are also different:

  • Newborns: 97.7 and 99.5°F (36.5 and 37.5°C).
  • Children: 96.8 and 99.5°F (36 and 37.5°C).

Certain illnesses, or incorrect temperature readings, could factor into why your thermometer reads 96°F (35.55°C), but you feel sick. Low body temperature could also be a symptom of a serious illness like hypothermia or sepsis, but you’d likely have severe symptoms.

Incorrect temperature taking

One common reason your thermometer may read 96°F (35.55°C) is because you took your temperature incorrectly.

  • Make sure you are following the manufacturer’s instructions for your thermometer.
  • Consider any factors that could have led to an inaccurate temperature. An oral reading may be affected if you’ve sipped a cold drink or kept your mouth open while taking your temperature. An armpit reading may be lower if you did not hold the thermometer in the correct place or if you improperly closed your arm.
  • Take your temperature a few times to make sure the reading is correct.

Hypothermia

Hypothermia occurs when your body is at 95°F (35°C) or lower in adults. For children and infants, it can occur when their temperature is lower than a reading in the normal range. Hypothermia is a very serious medical condition that can lead to death if not treated immediately by medical professionals.

This condition can occur because of exposure to cold weather, submersion in cold water, prolonged time in cold and wet clothes, or a cold home environment. An early symptom of hypothermia is shivering.

Hypothermia requires immediate medical attention, so you should call for emergency help if you suspect you have hypothermia. If you have to wait for medical help try to warm yourself up with blankets or a hot drink.

Sepsis

A drop in body temperature could be the symptom of sepsis. This occurs when your body starts fighting itself instead of an infection. It can damage to your tissues, shutdown your organs, and even lead to death. Other symptoms of sepsis include:

  • symptoms of infection
  • changes in mental state
  • feeling very sick, such as having a hard time breathing or feeling pain

Seek immediate medical help if you think you might have sepsis.

Keeping babies in a normal temperature range is very important to avoid hypothermia or other illnesses. Some factors that could influence a baby’s temperature include:

Take your baby’s temperature using the same method every time. Make sure the room is a comfortable temperature, and let the infant warm up if they have been brought in from the cold.

The best temperature-taking methods for infants and toddlers are:

  • In the armpit. Place the thermometer in the middle of the armpit, and close the arm against the body. Wait 3 minutes for an accurate measurement, or follow the thermometer’s instructions.
  • In the rectum. Put a protective sleeve over the thermometer and add a lubricant to it. Insert the tip of the thermometer in the rectum (no more than 2 centimeters) and wait 5 seconds before pulling it out and reading it, or follow the thermometer’s instructions.
  • In the eardrum (for infants more than 3 months old). Place the thermometer into the ear, sealing off the ear, and turn on the thermometer. Pull it out when the thermometer indicates it’s taken the reading.

There are other reasons your thermometer may read 96°F (35.55°C).

Hypothyroidism

Hypothyroidism occurs when your thyroid is not functioning properly. It does not create enough of your thyroid hormone for your body. Therefore, you may experience:

You can take medication to improve your thyroid’s hormone production.

Advanced age

You may have a lower body temperature as you age. You may have less body fat in your arms and legs, dry skin, and a slowed metabolism as you get older. These can all contribute to a lower body temperature.

Medications

Taking certain medications could lower your temperature. These include beta-blockers and some antipsychotics.

Exposure to cold temperatures

Your temperature may be low if you have been outside in cold weather. Wear warm enough clothes and keep your head covered in cold weather. Avoid getting wet in cold weather.

Call a healthcare professional if your temperature is 96°F (35.55°C) and you feel sick. You can describe your symptoms over the phone. They may offer a diagnosis or ask you to make an office visit.

You need immediate medical treatment if your temperature is dropping because of hypothermia or sepsis. Seek care if your temperature is declining and you have:

  • breathing difficulty
  • slowed speech
  • confusion or other mental changes
  • tiredness
  • blue skin or lips

Infants with a low body temperature should be seen by a doctor right away. Other symptoms of hypothermia in infants include red or discolored and cold skin, sleepiness, and disinterest in feeding.

There are several reasons you feel ill and have a thermometer reading of 96°F (35.55°C). You may have a serious illness like hypothermia or sepsis that requires immediate attention. You may have taken your temperature incorrectly. Or you may have another underlying factor contributing to the lower temperature like advanced age, medication use, or hypothyroidism.