Definition of clouds



Cloud type by altitude and latitude

Table 1
Level Genera Polar region Temperate region Tropical region
High Cirrus Cirrocumulus Cirrostratus 3 – 8 km (10 000 – 25 000 ft) 5 – 13 km (16 500 – 45 000 ft) 6 –18 km (20 000 – 60 000 ft)
Middle Altocumulus Altostratus Nimbostratus 2 – 4km (6 500 – 13 000 ft) 2 – 7 km (6 500 – 23 000 ft) 2 – 8 km (6 500 – 25 000 ft)
Low Stratus Stratocumulus Cumulus Cumulonimbus From the Earth’s surface to 2 km (0 – 6 500ft) From the Earth’s surface to 2 km (0 – 6 500ft) From the Earth’s surface to 2 km (0 – 6 500ft)


Cloud type by genera

Table 2
Description Troposphere
High level
  • Cirrus (Ci)
  • Cirrocumulus (Cc)
  • Cirrostratus (Cs)
Middle level
  • Altocumulus (Ac)
  • Altostratus (As)
  • Nimbostratus (Ns)
Low level
  • Stratocumulus (Sc)
  • Stratus (St)
  • Cumulus (Cu)
  • Cumulonimbus (Cb)


Cloud type by genera & species

Table 3
GENERA SPECIES
Designation Abbreviation Symbols Designation Abreviation
High altitude clouds: 6 –18 km
Cirrus Ci Fibratus fib
Cirrocumulus Cc Uncinus unc
Cirrostratus Cs spissatus spi
Middle clouds: 2 – 8 km
Altocumulus Ac castellanus cas
Altostratus As floccus flo
Nimbostratus Ns stratiformis str
Low altitude: rom the Earth’s surface to 2 km
Stratocumulus Sc nebulosus neb
Stratus St lenticularis len
Cumulus Cu fractus fra
Cumulus Cu humilis hum
Cumulus Cu mediocris med
Cumulus Cu congestus con
Cumulonimbus Cb volutus vol
Cumulonimbus Cb calvus cal
Cumulonimbus Cb capillatus cap