# Cloud cover

Also called: low cloud, mid cloud, high cloud, cirrus.

How much of the sky is covered by cloud, split into low, middle and high layers.

Low cloud (below about 2 km) and middle cloud are thick and block everything. High cloud — thin cirrus — is often barely visible at night but dims faint objects and brightens the sky, so it's worse than it looks for deep-sky observing.

**In AstroPilot:** AstroPilot forecasts cloud at all three heights, hour by hour, and shows a cloud map with satellite images and the week's forecast.

**Related:** [Transparency](https://astropilot.space/glossary/transparency.md), [Cloud map](https://astropilot.space/glossary/cloud-map.md), [Observing score](https://astropilot.space/glossary/observing-score.md)

From the AstroPilot astronomy glossary: https://astropilot.space/glossary/cloud-cover