I am not alive but I grow I don’t have lungs but I need air I don’t have a mouth, yet water kills me. What am I?

I look like a line, but I am not a fixed place. People often find the sun here.

at times harsh and others gentle, warm or cold I'm elemental capricious force and fickle friend yet sheer and shapeless in the end

I am born from water, but I do not come from underground. You feel me when It's cold enough for me to drift down. .

a noise in the dark tho all should be still a twig cracked behind u, an unearthly chill unseen I lurk in the fog and gloom a feeling you're not alone in your room a whisper in silence, a feeling of dread I chase away sleep when you're tucked in bed