| Code figure | Technical specifications |
Code figure | Non-technical specifications |
| 0 |
No CM clouds |
0 |
No Altocumulus, Altostratus or Nimbostratus
|
| 1 |
Altostratus translucidus
|
1 |
Altostratus, the greater part of which is semi-transparent; through this part the sun or moon may be
weakly visible, as through ground glass
|
| 2 |
Altostratus opacus or Nimbostratus
|
2 |
Altostratus, the greater part of which is sufficiently dense to hide the sun or moon, or Nimbostratus
|
| 3 |
Altocumulus translucidus at a single level
|
3 |
Altocumulus, the greater part of which is semi-transparent; the various elements of the cloud change
only slowly and are all at a single level
|
| 4 |
Patches (often lenticular) of Altocumulus translucidus, continually changing and occurring at one or more levels
|
4 |
Patches (often in the form of almonds or fish) of Altocumulus, the greater part of which is semi-transparent;
the clouds occur at one or more levels and the elements are continually changing in appearance
|
| 5 |
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
|
5 |
Semi-transparent Altocumulus in bands, or Altocumulus, in one or more fairly continuous layer (semi-transparent
or opaque), progressively invading the sky; these Altocumulus clouds generally thicken as a whole
|
| 6 |
Altocumulus cumulogenitus (or cumulonimbogenitus)
|
6 |
Altocumulus resulting from the spreading out of Cumulus (or Cumulonimbus)
|
| 7 |
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
|
7 |
Altocumulus in two or more layers, usually opaque in places, and not progressively invading the sky;
or opaque layer of Altocumulus, not progressively invading the sky; or Altocumulus together with Altostratus
or Nimbostratus
|
| 8 |
Altocumulus castellanus or floccus
|
8 |
Altocumulus with sproutings in the form of small towers or battlements, or Altocumulus having the appearance
of cumuliform tufts
|
| 9 |
Altocumulus of a chaotic sky, generally at several levels
|
9 |
Altocumulus of a chaotic sky, generally at several levels
|
| / |
CM clouds invisible owing to darkness, fog, blowing dust or sand, or other similar phenomena,
or because of a continuous layer of lower clouds
|
/ |
Altocumulus, Altostratus and Nimbostratus invisible owing to darkness, fog, blowing dust or sand, or other
similar phenomena, or more often because of the presence of a continuous layer of lower clouds
|