Cumulus (Cu)

Type: Low-level cloud

Height of cloud base: 1,200-6,000 ft

Cloud colour: White on its sunlit parts but with darker undersides.

Cloud shape: This cloud appears in the form of detached heaps like cotton wool. Shallow cumulus may appear quite ragged, especially in strong winds, but well formed clouds have flattened bases and sharp outlines. Large cumulus clouds have a distinctive 'cauliflower' shape.

Other cloud features: Well developed cumulus may produce showers.