Turns out that I do have a temperature. What they mean is that I don't have a fever.
I'm wondering how universal this saying is. Did you grow up hearing this, or do you maybe even say it, yourself? General age and location, if you don't mind.
The adults said it all the time when I was a kid. So we kids said it, too. I might have even said it while the Bratlings were growing up.
I'm older'n dirt, raised mostly in Texas and Louisiana.