This document describes and defines different types of clouds. It provides short descriptions of stratus, stratocumulus, nimbostratus, altocumulus, altostratus, cirrus, cirrocumulus, cirrostratus, cumulus, cumulonimbus, fog, mammatus, lenticular, and contrails clouds. The descriptions note key visual characteristics such as color, shape, texture, and formation of each cloud type.

2.  Stratus
 Stratocumulus
 Nimbostratus

3. Stratus
A low grey
cloud that
has a flat
base.

4. Stratocumulus
Large dark,
rounded
masses,
usually in
groups, lines,
or waves

5. Nimbostratus
Formless
cloud layer
that is
almost
uniformly
dark grey.

6.  Altocumulus
 Altostratus

7. Altocumulus
Grey, puffy
masses,
sometimes
rolled out in
parallel
waves or
bands.

8. Altostratus
Grey or
blue-grey
clouds that
usually cover
the entire
sky.

9.  Cirrus
 Cirrocumulus
 Cirrostratus

10. Cirrus
Thin and
whispy
clouds.

11. Cirrocumulus
A patch or
layer of
cloud
consisting of
tiny
individual
cloudlets.

12. Cirrostratus
Sheet-like
and nearly
transparent.

13.  Cumulus
 Cumulonimbus

14. Cumulus
Noticeable
vertical
development
and clearly
defined
edges.

15. Cumulonimbus
Towering
vertical cloud
that is very
tall, dense, and
involved in
thunderstorms
and other
inclement
weather.

16.  Fog
 Mammatus
 Lenticular
 Contrails

17. Fog
Suspended in
the air at or
near the
Earth's
surface.

18. Mammatus
Cellular
pattern of
pouches
hanging
underneath
the base of a
cloud.

19. Lenticular
Stationary
lens-shaped
clouds

20. Contrails
Artificial
clouds that
are the
visible trails
of condensed
water vapour
made by the
exhaust of
aircraft
engines.