What is a Normal Body Temperature?

What is a ‘normal’ body temperature? Many recent studies say 98.6 degrees F may be too high.

We all recognize 98.6 degrees F as our normal body temperature, but that number is far from exact. In fact, it’s just an average — established in 1868 by German doctor Carl Wunderlich, who took thousands of temperature readings from participants’ armpits with a cumbersome, footlong mercury thermometer that required up to 20 minutes to register.

Multiple recent studies seek to pinpoint the norm and have raised numerous other questions along the way. Several suggest 98.6 degrees F is too high. For instance, a 1992 U.S. Army–funded report found a mean body temperature of 98.2 degrees F, while a 2018 study using smartphones to record 5,038 oral temperatures suggested 97.7 degrees F. A 2002 meta review of 20 studies reaffirmed that our temps differ when taken in the mouth, ear, armpit, or rectum. But there are some caveats to all these readings:

Daily Flux

Your temperature fluctuates during the day, hitting a low between 3 and 5 a.m. and a peak between 4 and 6 p.m. The difference can be 1 degree F or more, depending on the individual.

Men and Women

The smartphone-based study found that men’s mean temperature was 0.18 degrees F lower than women’s. And normal body temperature decreases slightly as we age.

Fever Temperature

Wunderlich’s research 150 years ago fixed 100.4 degrees F as the flare-up of fever, a novel scientific marker for doctors to determine the onset of illnesses. The Army study determined that fever should be defined as 98.6 degrees F in the morning and 99.9 degrees F in the evening — but again taking into account bioindividuality.

 is an Experience Life deputy editor.

Related at Care2

30 comments

STEFANIE R
STEFANIE RACKS4 days ago

GOOD INFO THANK YOU

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Daniel N
John N5 days ago

thanks

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Christine V
Christine V5 days ago

I'm still going with 98.6

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Marija Mohoric
Marija Mohoric6 days ago

tks very much

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Jeramie D
Jeramie D6 days ago

Thanks

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Sherry Kohn
Sherry Kohn6 days ago

Many thanks to you !

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Mike R
Mike R6 days ago

Thanks

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Mark T
Mark Turner6 days ago

Ty.

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Hristina B
Hristina B6 days ago

I've had 35 even 34 and something. The "normal" indicated here is 37. That's way too high.

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ROSEMARY T
ROSEMARY T6 days ago

My normal is 97.6. Anything above that I have a fever.

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