cloud classification

Clouds can be classified either according to their form (i.e., cirrus, cumulus, and stratus) or their height (low, medium, and high clouds). The height of low clouds varies from 0 up to 6500 ft (2 km); medium clouds from 6500 to 13,000 ft (2–4 km) in polar regions and up to 20,000 ft (6 km) in temperate and tropical regions; and high clouds from 10,000 up to 25,000 ft (3–8 km) in polar regions and 20,000 up to 60,000 ft (6–18 or 19 km) in equatorial regions. The basic cloud forms are cirrocumulus, cirrostratus, cirrus, cumulus, stratus, and stratocumulus. These may be prefixed by alto if they exist above their normal level. Nimbus (nimbus) is a suffix often given to the rain-bearing clouds.

Cloud classification.

Notes: 1. Cloud base heights are higher than average in summer and lower in winter.

2. Cloud base heights are higher in equatorial latitudes than in polar latitudes.

Cloud classification.