Clouds and cloud types

In short: Clouds consist of tiny water droplets or ice crystals. They form when moist air rises, cools and the water vapour condenses.

In more detail: Clouds are classified by height and shape. The shape reveals much about the coming weather.

In detail

• High clouds: Cirrus (feather clouds) consist of ice. They often announce a change of weather.
• Mid-level clouds: Altocumulus (“sheep clouds”) and altostratus.
• Low clouds: Stratus (high fog), stratocumulus.
• Cumuliform clouds: Cumulus (heap clouds) in fair weather, cumulonimbus (thundercloud) with showers, hail and lightning (donner-und-blitz).
• Fog: A cloud near the ground.
• Cloud formation: Rising air cools, which is related to luftdruck-und-wetter.