Clouds and visibility

The four cloud families, the cloud base, how much of the sky is covered in eighths, and how far you can see. For pilots who fly by looking outside, these decide whether a flight can go.

What you learn

• Name cumulus, stratus, cirrus and cumulonimbus
• Explain what the cloud base is
• Read FEW, SCT, BKN and OVC as eighths of sky
• Give visibility in kilometres or metres
• Explain when and why fog forms

In playlists

• Weather

Also on

• Video course: Aviation for beginners
• Glossary: Ceiling
• Wiki: Cloud Formations