Cirrus fibratus, sometimes uncinus, not progressively invading the sky
12
Cirrus spissatus, in patches or entangled sheaves, which usually do not increase and sometimes seem to be the remains of the upper part of a Cumulonimbus; or Cirrus castellanus or floccus
13
Cirrus spissatus cumulonimbogenitus
14
Cirrus uncinus or fibratus, or both, progressively invading the sky; they generally thicken as a whole
15
Cirrus (often in bands) and Cirrostratus, or Cirrostratus alone, progressively invading the sky; they generally thicken as a whole, but the continuous veil does not reach 45 degrees above the horizon
16
Cirrus (often in bands) and Cirrostratus, or Cirrostratus alone, progressively Invading the sky; they generally thicken as a whole; the continuous veil extends more than 45 degrees above the horizon, without the sky being totally covered
17
Cirrostratus covering the whole sky
18
Cirrostratus not progressively invading the sky and not entirely covering it
19
Cirrocumulus alone, or Cirrocumulus predominant among the CH clouds
20
No CM clouds
21
Altostratus translucidus
22
Altostratus opacus or Nimbostratus
23
Altocumulus translucidus at a single level
24
Patches (often lenticular) of Altocumulus translucidus, continually changing and occurring at one or more levels
25
Altocumulus translucidus in bands, or one or more layers of Altocumulus translucidus or opacus, progressively invading the sky; these Altocumulus clouds generally thicken as a whole
26
Altocumulus cumulogenitus (or cumulonimbogenitus)
27
Altocumulus translucidus or opacus in two or more layers, or Altocumulus opacus in a single layer, not progressively invading the sky, or Altocumulus with Altostratus or Nimbostratus
28
Altocumulus castellanus or floccus
29
Altocumulus of a chaotic sky, generally at several levels
30
No CL clouds
31
Cumulus humilis or Cumulus fractus other than of bad weather,* or both
32
Cumulus mediocris or congestus, Towering cumulus (TCU), with or without Cumulus of species fractus or humilis or Stratocumulus, all having their bases at the same level
33
Cumulonimbus calvus, with or without Cumulus, Stratocumulus or Stratus
34
Stratocumulus cumulogenitus
35
Stratocumulus other than Stratocumulus cumulogenitus
36
Stratus nebulosus or Stratus fractus other than of bad weather,* or both
37
Stratus fractus or Cumulus fractus of bad weather,* or both (pannus), usually below Altostratus or Nimbostratus
38
Cumulus and Stratocumulus other than Stratocumulus cumulogenitus, with bases at different levels
39
Cumulonimbus capillatus (often with an anvil), with or without Cumulonimbus calvus, Cumulus, Stratocumulus, Stratus or pannus
40
CH
41
CM
42
CL
59
Cloud not visible owing to darkness, fog, duststorm, sandstorm, or other analogous phenomena
60
CH clouds invisible owing to darkness, fog, blowing dust or sand, or other similar phenomena, or because of a continuous layer of lower clouds
61
CM clouds invisible owing to darkness, fog, blowing dust or sand, or other similar phenomena, or because of continuous layer of lower clouds
62
CL clouds invisible owing to darkness, fog, blowing dust or sand, or other similar phenomena