I thought that aeroplane vapour trails were the cause of clouds. I think my mother told me at some point that the stuff that came out of the back of a plane was water vapour, which is what clouds are made from, and I interpreted this to mean that that was how all clouds were made. That and the cooling towers of a power plant near my home. I didn't think it was there specifically to make clouds, I just thought they were a side effect.
A childhood belief about weather

others believed things like this
- i used to believe that clouds were made from the thick smoke that came out of power plant towers.— Rick Shaw
- When I was a kid, I used to believe a nuclear plant was a clouds plant and could make magic clouds.— Tommy
- i used to believe that powers station cooling towers were where the clouds came fromAnon
- I used to think that the trails that Airplanes left in the sky, that's how clouds were made.Anon
- That all clouds were made by aeroplane exhaust fumes— diyjoe.com
- that Newport power station was where clouds were made. My dad is a known liar.— Lydia