Writing Notes: Breathing

I have a chapter in which my main character visits a cave. And while the air composition is different from Earth’s air, it got me thinking whether he would see a white cloud condensing from his breath.

Hot breath increases the relative humidity of the cold outside air as they mix. Once humidity reaches 100%, it results in breath condensation.

It may seem like a tiny thing when you describe setting & character, but it can provide indirect information to the reader.

If you want to know whether your or your character’s breath will condense into a white cloud in certain locations, you can use this calculator.

Jeno Marz
JENO MARZ is a science fiction writer from Latvia, Northern Europe, with background in electronics engineering and computer science. She is the author of two serial novels, Falaha’s Journey: A Spacegirl’s Account in Three Movements and Falaha’s Journey into Pleasure. Marz is current at work on a new SF trilogy. All her fiction is aimed at an adult audience.


  1. Cool! But yeah, I was beta reading for someone who described panicked breathing as the heart rate slowed down… which I found confusing enough that I suggested only mentioning one. Didn’t know if it was accurate or not, but I just got stuck there and it pulled me out of the story.
    My recent blog post: 4 Tips to Escape the Slush Pile

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