There are four different categories of clouds. High clouds, medium altitude clouds, lower clouds, and vertical tall clouds. They are broken down into ten genuses of clouds: Cirrus, Cirrocumulus, Cirrostratus, Altocumulus, Altostratus, Stratocumulus, Cumulus, Stratus, Cumulonimbus, and Nimbostratus.

Additionally there are 14 species, 9 types, and 9 additional phenomenons like Virga or Mammatus, but these are not really important in my question.

I find it troublesome to distinguish the Altocumulus, Stratocumulus and Cumulus clouds from each other. The hardest to distinguish in my opinion are the Stratocumulus and Altocumulus clouds. Even though I know, Ac are higher clouds than Sc, it is most of the time hard for me.

Can anyone point out any differences that would help me distinguish these genuses of clouds?


You are not alone. Allmost everyone has difficulty differentiating Ac from Sc because, apart from the obvious low clouds, you can't accurately discern a cloud's height purely from looking at it. For that you need a 'ceilometer', which is a vertical beam of light reflected off the cloud-base. Not many met sites have this.

  • $\begingroup$ Not exactly the answer I was looking for, but thanks, at least I know I'm not alone :) I'll still give you credit, but I found my answer elswhere. Would you want to add it to your post? windows2universe.org/earth/Atmosphere/clouds/… $\endgroup$ – KKZiomek Jun 15 '16 at 15:11
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    $\begingroup$ @KKZiomek; you mean "If the cloud is about the size of your fist, then it is stratocumulus"? That's a nice (very!) rough guide line, but Gordon's answer is still correct; very often you can't distinguish Ac from Sc. $\endgroup$ – Bart Jun 15 '16 at 15:19
  • $\begingroup$ @KKZiomek This meteorologist also agrees with Gordon (and Bart) as well. At some point cloud categorization has its limitations in both stratification and use, and this is about the area where it seems so to me in most circumstances. But hope that distinction did at least give you a good way to choose. :-) $\endgroup$ – JeopardyTempest Nov 2 '17 at 10:48

According to the WMO, your answer is as follows. (Note that you can use the width of your little finger held at arms length to estimate one degree and the width of three fingers held together at arms length to estimate five degrees.)

Altocumulus is distinguished from Stratocumulus by:

Most of the regularly arranged elements having, when observed at an angle of more than 30° above the horizon, an apparent width between 1 and 5°
Absence of any precipitation; Stratocumulus can have weak falls of rain, snow or snow pellets


Stratocumulus is distinguished from Altocumulus by:

Most of the regularly arranged elements having, when observed at an angle of more than 30° above the horizon, an apparent width greater than 5°
Possible precipitation in the form of weak falls of rain or snow


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