THE COMPLETE GUIDE TO

THE TEN DIFFERENT

TYPES OF CLOUDS
AND HOW TO IDENTIFY THEM
Dedicated to those who are passionately curious, keep their heads in the clouds, and
keep their eyes on the skies. And to Luke Howard, the father of cloud classification.
TABLE OF CONTENTS 4 Infographic

5 Introduction

12 Cirrus

18 Cirrocumulus

25 Cirrostratus

31 Altocumulus

38 Altostratus

45 Nimbostratus

51 Cumulonimbus

57 Cumulus

64 Stratus

71 Stratocumulus

79 Our Mission

80 Extras
Cloud Types: An Infographic

4
An Introduction to the 10 Different
Types of Clouds
⛅
Clouds are the equivalent of an ever-evolving painting
in the sky. They have the ability to make for magnificent
sunrises and spectacular sunsets. We’re surrounded by
clouds almost every day of our lives.

Let’s take the time and learn a little bit more about them!

The following information is presented to you as a

comprehensive guide to the ten different types of
clouds and how to idenify them.

Let’s just say it’s an instruction manual to the sky.

Here you’ll learn about the ten different cloud types:

their characteristics, how they differentiate from the
other cloud types, and much more.

So three cheers to you for starting on your cloud

identification journey.

Happy cloudspotting, friends!

The Three High Level Clouds

Cirrus (Ci) Cirrocumulus (Cc) Cirrostratus (Cs)

High, wispy streaks High-altitude cloudlets Pale, veil-like layer
Cirrus

High-altitude, thin, and wispy cloud

streaks made of ice crystals
cumulus
Cirro-

Small, flakey, and white high-

altitude cumulus patches
stratus
Cirro-
Cirrus

Thin, transparent, high-altitude layer

capable of producing a halo
The Three Middle Level Clouds

Altocumulus (Ac) Altostratus (As) Nimbostratus (Ns)

Mid-altitude cloud heaps Mid-altitude gray layer Precipitation layer
cumulus
Alto-

Middle-altitude cumulus clouds

arranged in groups or rolls
stratus

Featureless, gray layer cloud

Alto-

capable of masking the sun

Nimbo-
stratus
cumulus

Dark and featureless layer cloud

Alto-

responsible for rain and snow

The Three Low Level Clouds

Cumulonimbus (Cb) Cumulus (Cu) Stratus (St) Stratocumulus (Sc)

Thunderstorms Low, puffy, fair-weather Low, featureless layer Low, puffy layer
Cumulo-
nimbus

Dark-based storm cloud capable of

impressive vertical growth
Cumulus

Low-altitude, fluffy heaps of clouds

with cotton-like appearance
Cumulo-
Stratus
nimbus

Gray, featureless low-altitude cloud

capable of ground contact
cumulus
Cumulus
Strato-

Thicker, dark gray, and somewhat

conjoined heaps of clouds
The 5 Latin Terms of Cloud Types

Cirro- is translated from latin meaning ‘curl’.

The three clouds that include this term are cirrus, cirrocumulus, and cirrostratus. While
this term is translated as ‘curl’, that doesn’t mean these clouds are curly (though
cirrus clouds can be, which makes it an appropriate name). The important takeaway is
that these three clouds are found in the highest layer of the troposphere (the lowest
layer of the Earth’s atmosphere). These clouds are found at altitudes between
approximately 16,000-50,000 ft, or 5-15 km.

Cumulo- is translated from latin meaning ‘heap’.

The five clouds that include this term are cumulus, stratocumulus, cumulonimbus,
altocumulus, and cirrocumulus. Heap can also be described as piled or puffy. These
five clouds have at least some puffy and heap-like characteristics to them.

Strato- is translated from latin meaning ‘layer’.

The five clouds that include this term are stratus, stratocumulus, nimbostratus,
altostratus, and cirrostratus. A layer cloud is described as a cloud blanket that has
much less definition relative to a heap cloud.

Nimbo- is translated from latin meaning ‘rain’.

There are only two clouds that include the term ‘nimbo’: cumulonimbus and
nimbostratus. They are the only clouds that are regular producers of precipitation.

Alto- is translated from latin meaning ‘high’.

The two ‘alto’ clouds are altocumulus and altostratus. The translation is deceiving
because these clouds aren’t found in the highest part of the troposphere. Altocumulus
means they’re like cumulus clouds but found higher than regular cumulus clouds.
Similarly, altostratus are stratus clouds but found higher than stratus clouds. These
clouds are found at altitudes between approximately 7,000-23,000 ft, or 2-7 km.

9
The Contents of this Guide

The pages of this guide are organized in the following fashion.

Photographs. The images that have been selected are the best
examples of each cloud type for you to reference.

Descriptions. A summary of each cloud type is provided,

describing best how each cloud can be identified.

Cloud facts. Some facts about each cloud including its altitude,
Latin translation, abbreviation, and more.

Similar cloud types. Tips and tricks to help you make the
distinction from one cloud type to the next.

Cloud subtypes introduction. Did you know there are 34

subtypes that can be used to further classify a cloud?

Beyond the ten cloud types, there are fifteen cloud species,
nine cloud varieties, eleven supplementary features, four
accessory clouds, and five other kinds of clouds.

If you’re learning about this for the first time, don’t worry! We’ve
designed a cloud identification chart that can help you
visualize all cloud types and subtypes in a single infographic.
LET’S GET STARTED
 Cirrus
HIGH, WISPY STREAKS
Cirrus Clouds: High, Wispy Streaks
High-altitude, thin, and wispy cloud streaks composed of ice crystals

Cirrus clouds have a distinct look relative to the other nine cloud types. Because
cirrus clouds are made of ice crystals, they look different than your typical puffy cloud
shape, and can take on a number of different forms that resemble spider webs, fish
skeletons, mares’ tail, or hair-like commas. If you’re observing a cloud that’s fibrous in
nature, there’s a strong chance you’re looking at a cirrus cloud.

But all cirrus clouds don’t have that distinctive, fibrous shape. They can also be found
clumped together (spissatus cloud species), be entangled (intortus cloud variety), and
don’t look as majestic when you spot them closer to the horizon. Because of their ice
crystal composition, cirrus clouds are also capable of various optical phenomena
such as sun dogs and cloud iridescence.

Though human-formed, condensation trails from aircraft can become cirrus clouds in
the technical sense (homogenitus), created as a result of jet exhaust in cold
temperatures found in the upper parts of the troposphere.

Cirrus Cloud Facts

Cloud Level (Étage): High
Altitude/Height: 5-15 km (16,000-49,000 ft)
Latin Term: Derives from cirro-, meaning curl
Abbreviation: Cirrus can be abbreviated as Ci

Cloud Color: White to light gray Precipitation Potential: None

Sky Cover: Mostly sunny to sunny Cloud Frequency: Very common

13
Cirrus vs. Cirrocumulus

Both cirrus and cirrocumulus clouds are found at the same altitude, and a lot of times
when observing cirrocumulus clouds, you’ll see cirrus clouds in close proximation.
The biggest difference between the two is cirrocumulus clouds contain puffy cloudlets
and look like grains of rice, where cirrus clouds are more fibrous and wispy in nature.

Cirrus vs Cirrostratus

Cirrus and cirrostratus clouds are found at the same altitude and both can be fibrous
in nature. When deciding between the two, remember that a cirrostratus cloud
generally covers the sky and is more of a pale, veil-like layer cloud, where you’ll
generally see more individual elements in a cirrus cloud, such as comma shapes,
fishbone-like shapes, and other wispy designs.

14
Cirrus Cloud Species

Cirrus castellanus Cirrus fibratus Cirrus floccus

Rising towers, turrets Fiberlike, hairlike Puffy, ragged tufts

Cirrus spissatus Cirrus uncinus

Packed tightly, dense Curved, comma-shaped

Cirrus Cloud Varieties

Cirrus duplicatus Cirrus intortus Cirrus radiatus

Multilayered Interlaced, entangled Parallel bands and strips

Cirrus vertebratus
Fishbone-like, resembling ribs

15
Cirrus Cloud Supplementary Features

Cirrus fluctus Cirrus mamma

Kelvin-Helmholtz waves, curls Sac-like, resembling cow udders

Cirrus Cloud Accessories & Other Clouds

Cirrus homogenitus Cirrus homomutatus

Caused by human activity Mutated from a homogenitus

“A little cirrus, a touch of nimbostratus,

and a dash of cumulus!” - Zeus
Hercules (1997)

16
 Cirrus fibratus

Cirrus castellanus
Cirrocumulus
HIGH-ALTITUDE CLOUDLETS
Cirrocumulus Clouds: High-altitude Cloudlets
Small, flakey, and white high-altitude cumulus heaps and patches

Cirrocumulus clouds are thin cloud patches found high in the troposphere and are
the only cloud found at this altitude that has cloud heap characteristics. Because
cirrocumulus clouds are so high in altitude, the cloud heaps take on what can be
described as a ‘grain of rice’ appearance. Take note when you see them because
along with cumulonimbus, cirrocumulus clouds are the least seen among the ten
main cloud types.

Unlike cirrus and cirrostratus clouds, cirrocumulus clouds don’t typically produce
sun halos, though they are capable of iridescence and coronas on the rare
occasion. Additionally, these are the only clouds in the high level that cannot be
found in the fibrous form.

If you see a cirrocumulus cloud, the chances are good that there are cirrus or
cirrostratus clouds nearby. Similar to altocumulus clouds, cirrocumulus can also
take on a mackerel sky effect, resembling fish scales. If you’re lucky enough to see
a mackerel sky at sunset, you’re in for a treat.

Cirrocumulus Cloud Facts

Cloud Level (Étage): High
Altitude/Height: 5-15 km (16,000-49,000 ft)
Latin Term: Derives from cirro-, meaning curl, and cumulo-, meaning heap
Abbreviation: Cirrocumulus can be abbreviated as Cc

Cloud Color: White to light gray Precipitation Potential: Virga only

Sky Cover: Partly sunny to mostly sunny Cloud Frequency: Uncommon

19
Cirrocumulus vs. Cirrus

Both cirrocumulus and cirrus clouds are found at the same altitude, and a lot of times
when observing cirrocumulus clouds, you’ll see cirrus clouds in close proximation.
The biggest difference between the two is cirrocumulus clouds contain puffy cloudlets
and look like grains of rice, where cirrus clouds are more fibrous and wispy in nature.

Cirrocumulus vs. Cirrostratus

Cirrocumulus and cirrostratus clouds are both found at the same altitude and can be
seen in close proximation with one another. If you’re deciding between the two, and
the cloud in question is featureless, or perhaps somewhat fibrous, chances are you’re
observing a cirrostratus cloud. Cirrocumulus clouds contain more features than
cirrostratus clouds, whereas a cirrostratus cloud is more of a featureless layer.

20
Cirrocumulus vs. Altocumulus

Cirrocumulus and altocumulus clouds share many of the same cloud species, but
cirrocumulus clouds are higher in altitude, so their cloud patches appear smaller.
Cirrocumulus clouds are more often than not seen with cirrus and cirrostratus clouds
in near proximity. Altocumulus clouds are also much more commonly observed than
cirrocumulus. It’s more common to see the entire sky covered by a layer of
altocumulus clouds than cirrocumulus clouds.

Cirrocumulus stratiformis

21
Cirrocumulus Cloud Species

Cirrocumulus castellanus Cirrocumulus floccus Cirrocumulus lenticularis

Rising towers, turrets Puffy, ragged tufts Lens-shaped, resembling a UFO

Cirrocumulus stratiformis
Horizontal, layer-like form

Cirrocumulus Cloud Varieties

Cirrocumulus lacunosus Cirrocumulus undulatus

Perforated, round frayed holes Wavelike, undulating

22
Cirrocumulus Cloud Supplementary Features

Cirrocumulus cavum Cirrocumulus mamma Cirrocumulus virga

Fallstreak hole, hole punch Sac-like, resembling cow udders Evaporating rain strips

Cirrocumulus Cloud Accessories & Other Clouds

Cirrocumulus homomutatus
Mutated from a homogenitus

“A slight breeze from the southeast and some

high cirrocumulus to the west.” - Jeeves

Jeeves and Wooster, Season 2 Episode 4

23
 Cirrocumulus undulatus

Cirrocumulus floccus
Cirrostratus
PALE, VEIL-LIKE LAYER
Cirrostratus Clouds: Pale, Veil-like Layer
Thin, transparent, high-altitude cloud layer capable of producing a 22° halo

Cirrostratus clouds can best be described as a thin cloud blanket high up in the
troposphere spread out across the sky. Found at the same altitude as their cirrus and
cirrocumulus counterparts, these clouds are more widely known for being the culprit
of sun and moon halos, as they’re composed of ice crystals.

Like most layer clouds, cirrostratus clouds can take on a relatively dull appearance.
They have very few cloud species and varieties associated with them. One distinction
that cirrostratus clouds have going for them however is that they’re one of two clouds
that can be fibrous in appearance (cloud species fibratus). They’re also one of two
clouds, that can take on a hazy, nebulous feel (cloud species nebulosus), which is
where the cloud completely lacks any kind of discernible detail. There are instances
where they might take on a wavelike appearance (cloud variety undulatus) as well.

Because cirrostratus clouds are generally very thin, the sun will always be visible,
which might help you distinguish it from its close relative, the altostratus cloud.
Sometimes cirrostratus clouds are so thin, they’re almost difficult to even make out.

Cirrostratus Cloud Facts

Cloud Level (Étage): High
Altitude/Height: 6-13 km (20,000-43,000 ft)
Latin Term: Derives from cirro-, meaning curl, and strato-, meaning layer
Abbreviation: Cirrostratus can be abbreviated as Cs

Cloud Color: White to light gray Precipitation Potential: None

Sky Cover: Partly sunny to mostly sunny Cloud Frequency: Common

26
Cirrostratus vs. Cirrus

Cirrostratus and cirrus clouds are found at the same altitude and both can be fibrous
in nature. When deciding between the two, remember that a cirrostratus cloud
generally covers the sky and is more of a pale, veil-like layer cloud, where you’ll
generally see more individual elements in a cirrus cloud, such as comma shapes,
fishbone-like shapes, and other wispy designs.

Cirrostratus vs. Cirrocumulus

Cirrostratus and cirrocumulus clouds are both found at the same altitude and can be
seen in close proximation with one another. If you’re deciding between the two, and
the cloud in question is featureless, or perhaps somewhat fibrous, chances are you’re
observing a cirrostratus cloud. Cirrocumulus clouds contain more features than
cirrostratus clouds, whereas a cirrostratus cloud is more of a featureless layer.

27
Cirrostratus vs. Altostratus

Cirrostratus and altostratus clouds are both layer clouds. A key difference is that if
you see an optical phenomena in a cloud and are trying to decide between the two,
you’re probably looking at a cirrostratus cloud. Cirrostratus clouds are lighter in color,
you can always see the sun’s position through a cirrostratus cloud, which is not
always the case with altostratus clouds, which are darker and lower to the ground.

“Well it would if they were altocumulus, not cirrostratus.

Get your clouds right.” - Dwight Schrute

The Office, Season 5 Episode 13

28
Cirrostratus Cloud Species

Cirrostratus fibratus Cirrostratus nebulosus

Fiberlike, hairlike Full of vapor, lacking detail

Cirrostratus Cloud Varieties

Cirrostratus duplicatus Cirrostratus undulatus

Multilayered Wavelike, undulating

Cirrostratus Cloud Accessories & Other Clouds

Cirrostratus homomutatus
Mutated from a homogenitus

29
 Cirrostratus nebulosus

Cirrostratus nebulosus
Altocumulus
MID-ALTITUDE CLOUD HEAPS
Altocumulus Clouds: Mid-altitude Cloud Heaps
Middle-altitude cumuliform clouds often arranged in heaps or rolls

Altocumulus clouds are typically found in groups or heaps clumped together. They’re
found in the middle layer of the troposphere, lower than cirrocumulus and higher than
their cumulus and stratocumulus counterparts. The term mackerel sky is also
common to altocumulus (and cirrocumulus) clouds that display a pattern resembling
fish scales. Of all the ten different cloud types, altocumulus clouds are one of the
most diverse and dynamic in terms of their appearance.

These clouds can take on a handful of shapes and sizes. They can include cloud
heaps that resemble towering castles (castellanus cloud species), can sometimes
resemble a lock of wool (cloud species floccus), can cover the entire sky (stratiformis
cloud species), and can even come in the shape of roll clouds (volutus cloud species).

Altocumulus are also known for creating UFO-shaped clouds (lenticularis cloud
species), are responsible for a lot of the uncommon fallstreak hole sightings you might
be lucky enough to see (cavum cloud feature), and on the rarest of occasion, can
produce a wavy, chaotic appearance (asperitas cloud feature).

Altocumulus Cloud Facts

Cloud Level (Étage): Middle
Altitude/Height: 2-7 km (7,000-23,000 ft)
Latin Term: Derives from alto-, meaning high, and cumulo-, meaning heap
Abbreviation: Altocumulus can be abbreviated as Ac

Cloud Color: White to gray Precipitation Potential: Virga only

Sky Cover: Mostly cloudy to mostly sunny Cloud Frequency: Very common

32
Altocumulus vs. Altostratus

While altocumulus and altostratus clouds are found at the same altitude, altostratus
clouds are generally a featureless layer, where altocumulus clouds typically have
plenty of features. Altostratus clouds are absent of cloud species, so if you’re
deciding between an altostratus and altocumulus cloud and what you’re observing
looks to have an associated cloud species, you should lean towards an altocumulus.

Altocumulus vs. Cirrocumulus

Altocumulus and cirrocumulus clouds share many of the same cloud species, but
cirrocumulus clouds are higher in altitude, so their cloudlets are smaller. Cirrocumulus
clouds are found with cirrus and cirrostratus clouds in near proximity. Altocumulus
clouds are also more commonly observed than cirrocumulus. It’s more common to
see the sky covered by a layer of altocumulus clouds than cirrocumulus clouds.

33
Altocumulus vs. Cumulus

Altocumulus clouds are generally seen as patches of clouds grouped together, either
in rolls, sheets, or heaps. Cumulus clouds are more often seen as individual clouds.
Cumulus clouds are also much closer to the ground. A key reminder trying to
determine the difference between cumulus and altocumulus clouds are that the two
cloud types don’t have any shared cloud species.

Altocumulus vs. Stratocumulus

Altocumulus clouds are more closely related to stratocumulus clouds than they are to
cumulus clouds. They share almost all of the same cloud species, cloud varieties, and
other cloud features. Their altitude is their biggest differentiator, with stratocumulus
clouds being closer to the ground. Stratocumulus cloud formations are seemingly
bigger, and are generally a bit darker than altocumulus clouds.

34
Altocumulus Cloud Species

Altocumulus castellanus Altocumulus floccus Altocumulus lenticularis

Rising towers, turrets Puffy, ragged tufts Lens-shaped, resembling a UFO

Altocumulus stratiformis Altocumulus volutus

Horizontal, layer-like form Tube-shaped roll cloud

Altocumulus Cloud Varieties

Altocumulus duplicatus Altocumulus lacunosus Altocumulus opacus

Multilayered Perforated, round frayed holes Opaque, masks the sun

Altocumulus perlucidus Altocumulus radiatus Altocumulus translucidus

Transparent by small gaps Parallel bands and strips See-through, sun’s position visible

35
Altocumulus Cloud Varieties (cont.)

Altocumulus undulatus
Wavelike, undulating

Altocumulus Cloud Supplementary Features

Altocumulus asperitas Altocumulus cavum Altocumulus fluctus

Chaotic, wavy underneath Fallstreak hole, hole punch Kelvin-Helmholtz waves, curls

Altocumulus mamma Altocumulus virga

Sac-like, resembling cow udders Evaporating rain strips

36
 Altocumulus stratiformis

Altocumulus floccus
Altostratus
MID-ALTITUDE GRAY LAYER
Altostratus Clouds: Mid-altitude Gray Layer
Sheet of featureless, gray clouds in the middle cloud level capable of
masking the sun

Altostratus clouds are found in the middle cloud level. Unlike their altocumulus
counterpart, they’re often boring to look at. Along with nimbostratus clouds, these
clouds don’t have any species associated with them.

But they do come with a handful of cloud varieties, which can help you make the
determination if you’re looking at an altostratus cloud. If you see a cloud covering the
sky’s entirety that’s not very close to the ground, and it’s positioned such that it’s
visible through the clouds but giving off a ‘frosted glass’ appearance, chances are
good that you’re observing a cloud classified as altostratus translucidus. If the cloud
is opaque and you can’t see the sun’s position, consider it an altostratus opacus.

These clouds can also be responsible for precipitation, though it’s short-lived and not
common. You might also find scud clouds (pannus cloud accessory) underneath the
main cloud layer, which can be one more indication that you’re looking at an
altostratus cloud.

Altostratus Cloud Facts

Cloud Level (Étage): Middle
Altitude/Height: 2-7 km (7,000-23,000 ft)
Latin Term: Derives from alto-, meaning high, and strato- meaning layer
Abbreviation: Altostratus can be abbreviated as As

Cloud Color: Gray to dark gray Precipitation Potential: Uncommon

Sky Cover: Cloudy to mostly cloudy Cloud Frequency: Common

39
Altostratus vs. Altocumulus

While altostratus and altocumulus clouds are found at the same altitude, altostratus
clouds are generally a featureless layer, where altocumulus clouds typically have
plenty of features. Altostratus clouds are absent of cloud species, so if you’re
deciding between an altostratus and altocumulus cloud and what you’re observing
looks to have an associated cloud species, you should lean towards an altocumulus.

Altostratus vs. Cirrostratus

Cirrostratus and altostratus clouds are both layer clouds. A key difference is that if
you see an optical phenomena in a cloud and are trying to decide between the two,
you’re probably looking at a cirrostratus cloud. Cirrostratus clouds are lighter in color,
you can always see the sun’s position through a cirrostratus cloud, which is not
always the case with altostratus clouds, which are darker and lower to the ground.

40
Altostratus vs. Stratocumulus

Altostratus clouds are generally a featureless layer cloud, whereas stratocumulus

clouds have more detail. Remember, if you’re trying to decide between an altostratus
and stratocumulus cloud, and the cloud being observed has been determined to have
an associated cloud species, it’s not an altostratus cloud.

Altostratus vs. Stratus

Both altostratus clouds and stratus clouds are both layer clouds, so they can certainly
look the same. Altostratus clouds are higher in altitude though, which means they
won’t touch the ground or mask the tops of tall buildings like a stratus cloud would.
When deciding between these clouds, if you’re able to see further off in the distance,
chances are likely that you’re looking at an altostratus cloud.

41
Altostratus Cloud Varieties

Altostratus duplicatus Altostratus opacus Altostratus radiatus

Multilayered Opaque, masks the sun Parallel bands and strips

Altostratus translucidus Altostratus undulatus

See-through, sun’s position visible Wavelike, undulating

Altostratus Cloud Supplementary Features

Altostratus mamma Altostratus praecipitatio Altostratus virga

Sac-like, resembling cow udders Precipitation reaching the surface Evaporating rain strips

42
Altostratus Cloud Accessories & Other Clouds

Altostratus pannus
Ragged frazzles, scud

Altostratus opacus

43
 Altostratus opacus

Altostratus undulatus
Nimbostratus
PRECIPITATION LAYER
Nimbostratus Clouds: Precipitation Layer
Dark and featureless layer cloud responsible for rainy and snowy weather

Nimbostratus clouds are associated with rainy, dreary days. They’re also responsible
for snowy weather. Either way, these clouds are best known precipitation (and might
be the cause for your outdoor activities to be postponed).

Though it’s difficult to tell visually, these clouds can be put into the category of
multilevel clouds, meaning the base of a nimbostratus cloud can be found relatively
close to the ground, but the tops of them can extend upwards into the middle cloud
level. The thickness of a nimbostratus cloud helps give it a darker appearance than
most.

Of the ten main cloud types, only two are consistent precipitation producers:
nimbostratus and cumulonimbus. Nimbostratus are responsible for continuous
precipitation where cumulonimbus are more likely associated with more dramatic
weather, including quick-hitting extreme downpours. So if it’s raining, and has been
raining all day, you’re in the presence of a nimbostratus cloud.

Nimbostratus Cloud Facts

Cloud Level (Étage): Middle, though its cloud base extends into the lower level
Altitude/Height: 0.5-5.5 km (2,000-18,000 ft)
Latin Term: Derives from nimbo-, meaning rain, and strato-, meaning layer
Abbreviation: Nimbostratus can be abbreviated as Ns

Cloud Color: Light gray to very dark gray Precipitation Potential: Always

Sky Cover: Cloudy to mostly cloudy Cloud Frequency: Common

46
Nimbostratus vs. Cumulonimbus

Both cumulonimbus clouds and nimbostratus clouds have precipitation, and when
underneath them, it might be tough to differentiate the two. If the precipitation is
particularly heavy, or if the rain is accompanied by thunder, lightning, or other cloud
features like a wall cloud (murus cloud feature), shelf cloud (arcus cloud feature), or a
tail cloud (cauda cloud feature), you’re under a cumulonimbus cloud.

Nimbostratus vs. Stratocumulus

When deciding between nimbostratus and stratocumulus clouds, remember that

nimbostratus clouds are associated with precipitation, where stratocumulus clouds
only produce precipitation in certain conditions. Nimbostratus clouds are generally
featureless and don’t have any associated cloud species or varieties, while
stratocumulus clouds have plenty of species and varieties to go around.

47
Nimbostratus vs. Stratus

Both nimbostratus and stratus cloud bases can be found at the same height, are both
relatively featureless, and are both the same light gray to dark gray color. The biggest
differentiator is that nimbostratus clouds contain rain, whereas stratus clouds only
precipitate on certain occasions. If it’s raining, chances are it’s a nimbostratus cloud. If
it isn’t, it’s a stratus cloud.

Nimbostratus pannus

48
Nimbostratus Cloud Supplementary Features

Nimbostratus praecipitatio Nimbostratus virga

Precipitation reaching the surface Evaporating rain strips

Nimbostratus Cloud Accessories & Other Clouds

Nimbostratus pannus
Ragged frazzles, scud

Nimbostratus praecipitatio

49
 Nimbostratus pannus

Nimbostratus praecipitatio
 Cumulonimbus
MS THUNDERSTORMS
Cumulonimbus Clouds: Thunderstorms
Dark-based storm cloud capable of impressive vertical growth and
heavy precipitation

Cumulonimbus clouds are responsible for stormy weather. If you’re looking up at a

cloud that’s causing rainy and windy conditions, creating hail, thunder, and lightning,
chances are you got yourself a cumulonimbus cloud.

If you’re observing this cloud from a distance, what will stand out most is the cloud’s
impressive height, as it’s the only cloud that extends through all three cloud levels. Its
base can be very low to the ground, and its top can extend to the highest layer of the
troposphere. The top of the cloud might take on a bald appearance (calvus cloud
species), or it can take on a hairy and fibrous upper portion (capillatus cloud species).

The more potent cumulonimbus clouds can create a handful of cloud features. Above
the main cloud, an anvil cloud (incus cloud feature) can form, where the cloud hits the
top of the troposphere and spreads out across the sky. Additionally, you might find the
most dramatic examples of mammatus clouds (mamma cloud feature) in the upper
portion of a cumulonimbus, caused by pockets of cool, sinking air.

Cumulonimbus Cloud Facts

Cloud Level (Étage): Low, though it extends into the middle and high levels
Altitude/Height: 0.5-16 km (2,000-52,000 ft)
Latin Term: Derives from cumulo-, meaning heap, and nimbo-, meaning rain
Abbreviation: Cumulonimbus can be abbreviated as Cb

Cloud Color: Light gray to very dark gray Precipitation Potential: Very common

Sky Cover: Cloudy to partly sunny Cloud Frequency: Uncommon

52
Cumulonimbus vs. Cumulus

Fully developed cumulonimbus clouds are much different than typical fair-weather
cumulus clouds, but a cumulus congestus cloud is the precursor to a cumulonimbus
cloud. If you’re trying to decide between the two, and the cloud in question has
precipitation, lightning, or a fibrous upper portion, you can consider it a
cumulonimbus cloud. Otherwise, it would be identified as a cumulus cloud.

Cumulonimbus vs. Nimbostratus

Both cumulonimbus clouds and nimbostratus clouds have precipitation, and when
underneath them, it might be tough to differentiate the two. If the precipitation is
particularly heavy, or if the rain is accompanied by thunder, lightning, or other cloud
features like a wall cloud (murus cloud feature), shelf cloud (arcus cloud feature), or a
tail cloud (cauda cloud feature), you’re under a cumulonimbus cloud.

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Cumulonimbus Cloud Species

Cumulonimbus calvus Cumulonimbus capillatus

Without cirriform, hairless Fibrous upper portion

Cumulonimbus Cloud Supplementary Features

Cumulonimbus arcus Cumulonimbus cauda Cumulonimbus incus

Shelf cloud, gust collar Tail cloud, attached to murus Anvil above a cumulonimbus

Cumulonimbus mamma Cumulonimbus murus Cumulonimbus praecipitatio

Sac-like, resembling cow udders Wall cloud, cloud lowering Precipitation reaching the surface

Cumulonimbus tuba Cumulonimbus virga

Funnel cloud, tornado Evaporating rain strips

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Cumulonimbus Cloud Accessories & Other Clouds

Cumulonimbus flumen Cumulonimbus pannus Cumulonimbus pileus

Beaver tail, detached from murus Ragged frazzles, scud Cap or hood over a cumuliform

Cumulonimbus velum Cumulonimbus flammagenitus

Horizontal cloud veil Pyrocumulus, caused from fire

“See? Cumulonimbus.” - Russell

Up (2009)

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 Cumulonimbus calvus

Cumulonimbus arcus
 Cumulus
LOW, PUFFY, FAIR-WEATHER
Cumulus Clouds: Low, Puffy, Fair-weather
Low-altitude, fluffy heaps of clouds with cotton-like appearance

Cumulus clouds are the clouds that we all drew as kids. They’re cotton ball clouds,
popcorn clouds, and the clouds in the opening scene of The Simpsons. Though they
come in different shapes and sizes, they’re generally the easiest type of cloud to pick
out of the ten different cloud types. When the average person is asked to visualize a
cloud, cumulus clouds are generally the first to come to mind.

The different sizes of cumulus clouds are described by their four associated species.
If the cumulus cloud you’re looking at is wider than it is tall, then it’s a cumulus
humilis. If it’s as wide as it is tall, then it’s a cumulus mediocris. But when a cumulus
cloud is taller than it is wide, known as cumulus congestus, things can get interesting.
If a cumulus congestus cloud continues its vertical growth, they’re capable of
producing rain, and can eventually morph into a cumulonimbus cloud.

Finally, if you see a cumulus cloud that’s ragged and broken up, consider it of the
species cumulus fractus. You might witness these clouds in the evening as cumulus
clouds begin to dissipate, or perhaps on a windy day.

Cumulus Cloud Facts

Cloud Level (Étage): Low, but capable of extending into higher levels (congestus)
Altitude/Height: 0.2-2 km (2,000-7,000 ft)
Latin Term: Derives from cumulo-, meaning heap
Abbreviation: Cumulus can be abbreviated as Cu

Cloud Color: White to gray Precipitation Potential: Uncommon

Sky Cover: Mostly sunny to sunny Cloud Frequency: Very common

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Cumulus vs. Altocumulus

Altocumulus clouds are generally seen as patches of clouds grouped together, either
in rolls, sheets, or heaps. Cumulus clouds are more often seen as individual clouds.
Cumulus clouds are also much closer to the ground. A key reminder trying to
determine the difference between cumulus and altocumulus clouds are that the two
cloud types don’t have any shared cloud species.

Cumulus vs. Stratocumulus

Both cumulus and stratocumulus clouds are found at the same height, but
stratocumulus clouds are more of a layer cloud than a cumulus cloud, usually found in
conjoined groups or clumps of clouds. Additionally, stratocumulus clouds are
generally darker than cumulus clouds. It’s also important to note that both clouds
don’t share any cloud species or varieties besides the radiatus cloud variety.

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Cumulus vs. Cumulonimbus

Fully developed cumulonimbus clouds are much different than typical fair-weather
cumulus clouds, but a cumulus congestus cloud is the precursor to a cumulonimbus
cloud. If you’re trying to decide between the two, and the cloud in question has
precipitation, lightning, or a fibrous upper portion, you can consider it a
cumulonimbus cloud. Otherwise, it would be identified as a cumulus cloud.

“So when you shot it up into the stratosphere you

figured it would induce a molecular phase change of
the vapor from the cumulonimbus layer?” - Sam Sparks
Cloudy With a Chance of Meatballs (2009)

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Cumulus Cloud Species

Cumulus congestus Cumulus fractus Cumulus humilis

Vertical, cauliflower outline Ragged, broken up Flattened, wider than it is tall

Cumulus mediocris
Medium height, tall as it is wide

Cumulus Cloud Varieties

Cumulus radiatus
Parallel bands and strips

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Cumulus Cloud Supplementary Features

Cumulus arcus Cumulus fluctus Cumulus praecipitatio

Shelf cloud, gust collar Kelvin-Helmholtz waves, curls Precipitation reaching the surface

Cumulus tuba Cumulus virga

Funnel cloud, tornado Evaporating rain strips

Cumulus Cloud Accessories & Other Clouds

Cumulus pannus Cumulus pileus Cumulus velum

Ragged frazzles, scud Cap or hood over a cumuliform Horizontal cloud veil

Cumulus cataractagenitus Cumulus flammagenitus Cumulus homogenitus

Waterfall condensation and spray Pyrocumulus, caused from fire Caused by human activity

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 Cumulus

Cumulus humilis
 Stratus
LOW, FEATURELESS LAYER
Stratus Clouds: Low, Featureless Layer
Gray, featureless low-altitude layer cloud capable of ground contact

When you think of a cloudy, dreary day, you might have stratus clouds on your mind.
Stratus clouds are blanket clouds that sit low to the ground, and on occasion, come in
contact with the ground, better known as fog. If you’re a city dweller, you might know
stratus clouds by their ability to obscure the tops of tall buildings.

These clouds only have two species associated with them: nebulosus and fractus.
Stratus nebulosus clouds are arguably the dullest of the clouds out there. They’re
featureless, lack detail, and probably wouldn’t be considered picturesque. Stratus
fractus aren’t exactly picturesque either, but at least there’s a little detail, as these
clouds are broken up shards of stratus clouds.

Depending on the conditions, stratus clouds can mask the sun (opacus cloud variety),
though sometimes the sun can be observed (translucidus cloud variety). It’s also
possible to find wavelike, undulating features in them (undulatus cloud variety).
Regardless, stratus clouds aren’t the most memorable cloud and often leave you
wishing for sunnier days.

Stratus Cloud Facts

Cloud Level (Étage): Low
Altitude/Height: 0-2 km (0-7,000 ft)
Latin Term: Derives from strato-, meaning layer
Abbreviation: Stratus can be abbreviated as St

Cloud Color: Gray to dark gray Precipitation Potential: Uncommon

Sky Cover: Cloudy to mostly cloudy Cloud Frequency: Common

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Stratus vs. Altostratus

Both altostratus clouds and stratus clouds are both layer clouds, so they can certainly
look the same. Altostratus clouds are higher in altitude though, which means they
won’t touch the ground or mask the tops of tall buildings like a stratus cloud would.
When deciding between these clouds, if you’re able to see further off in the distance,
chances are likely that you’re looking at an altostratus cloud.

Stratus vs. Stratocumulus

Both stratus and stratocumulus clouds are found at the same altitude. But if you’re
deciding between a stratus and stratocumulus cloud, remember that stratus clouds
are generally featureless layer clouds. On the contrary, stratocumulus clouds can
contain plenty of features. Both clouds don’t share any of the same cloud species,
which can help differentiate the two.

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Stratus vs. Nimbostratus

Both nimbostratus and stratus cloud bases can be found at the same height, are both
relatively featureless, and are both the same light gray to dark gray color. The biggest
differentiator is that nimbostratus clouds contain rain, whereas stratus clouds only
precipitate on certain occasions. If it’s raining, chances are it’s a nimbostratus cloud. If
it isn’t, it’s a stratus cloud.

“Hilary Banks doesn’t know the difference between a cirrus

cloud and a stratus cloud… what is the difference?” - Will

The Fresh Prince of Bel Air, Season 4 Episode 15

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Stratus Cloud Species

Stratus fractus Stratus nebulosus

Ragged, broken up Full of vapor, lacking detail

Stratus Cloud Varieties

Stratus opacus Stratus translucidus Stratus undulatus

Opaque, masks the sun See-through, sun’s position visible Wavelike, undulating

Stratus Cloud Supplementary Features

Stratus fluctus Stratus praecipitatio

Kelvin-Helmholtz waves, curls Precipitation reaching the surface

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Stratus Cloud Accessories & Other Clouds

Stratus cataractagenitus Stratus homogenitus Stratus silvagenitus

Waterfall condensation and spray Caused by human activity Evaporation from a forest

Stratus opacus

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 Stratus nebulosus

Stratus
 Stratocumulus
ER LOW, PUFFY LAYER
Stratocumulus Clouds: Low, Puffy Layer
Thicker, low-altitude, and somewhat conjoined heaps of clouds

Consider stratocumulus clouds a mix of stratus and cumulus clouds, hence the name
(strato- and cumulo- are latin for layer and heap, respectively). They’re a layer of puffy
clouds, and can usually be found as conjoined heaps, similar to altocumulus clouds.
In many ways, these clouds are like altocumulus clouds closer to the ground.

Similar to altocumulus, stratocumulus clouds come in many different shapes and

sizes and have a handful of associated species, varieties, and features, more than any
of the ten main cloud types in fact. They come in various cloud species that describe
forms of rising turret formations (castellanus cloud species), wooly locks (floccus
cloud species), smooth lens shaped (lenticularis cloud species), layer form blanketing
the sky (stratiformis cloud species), and even as a roll cloud (volutus cloud species).

More dramatic versions of stratocumulus clouds include (but aren’t limited to) chaotic
and wavy features (asperitas cloud feature), sac-like features (mamma cloud feature),
and can even have the rare Kelvin-Helmholtz wave cloud (fluctus cloud feature)
association. Stratocumulus clouds are diverse and capable of many different looks.

Stratocumulus Cloud Facts

Cloud Level (Étage): Low
Altitude/Height: 0.2-2 km (2,000-7,000 ft)
Latin Term: Derives from strato-, meaning layer, and cumulo-, meaning heap
Abbreviation: Stratocumulus can be abbreviated as Sc

Cloud Color: Light gray to dark gray Precipitation Potential: Uncommon

Sky Cover: Mostly cloudy to mostly sunny Cloud Frequency: Very common

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Stratocumulus vs. Altocumulus

Stratocumulus clouds are more closely related to altocumulus clouds than they are to
cumulus clouds. They share almost all of the same cloud species, cloud varieties, and
other cloud features. Their altitude is their biggest differentiator, with stratocumulus
clouds being closer to the ground. Stratocumulus cloud formations are seemingly
bigger, and are generally a bit darker than altocumulus clouds.

Stratocumulus vs. Altostratus

Stratocumulus clouds have more detail, whereas altostratus clouds are generally a
featureless layer cloud. Remember, if you’re trying to decide between an altostratus
and stratocumulus cloud, and the cloud being observed has been determined to have
an associated cloud species, it’s not an altostratus cloud.

73
Stratocumulus vs. Cumulus

Both stratocumulus and cumulus clouds are found at the same height, but
stratocumulus clouds are more of a layer cloud than a cumulus cloud, usually found in
conjoined groups or clumps of clouds. Additionally, stratocumulus clouds are
generally darker than cumulus clouds. It’s also important to note that both clouds
don’t share any cloud species or varieties besides the radiatus cloud variety.

Stratocumulus vs. Nimbostratus

When deciding between nimbostratus and stratocumulus clouds, remember that

nimbostratus clouds are associated with precipitation, where stratocumulus clouds
only produce precipitation in certain conditions. Nimbostratus clouds are generally
featureless and don’t have any associated cloud species or varieties, while
stratocumulus clouds have plenty of species and varieties to go around.

74
Stratocumulus vs. Stratus

Both stratus and stratocumulus clouds are found at the same altitude. But if you’re
deciding between a stratus and stratocumulus cloud, remember that stratus clouds
are generally featureless layer clouds. On the contrary, stratocumulus clouds can
contain plenty of features. Both clouds don’t share any of the same cloud species,
which can help differentiate the two.

Stratocumulus floccus

75
Stratocumulus Cloud Species

Stratocumulus castellanus Stratocumulus floccus Stratocumulus lenticularis

Rising towers, turrets Puffy, ragged tufts Lens-shaped, resembling a UFO

Stratocumulus stratiformis Stratocumulus volutus

Horizontal, layer-like form Tube-shaped roll cloud

Stratocumulus Cloud Varieties

Stratocumulus duplicatus Stratocumulus lacunosus Stratocumulus opacus

Multilayered Perforated, round frayed holes Opaque, masks the sun

Stratocumulus perlucidus Stratocumulus radiatus Stratocumulus translucidus

Transparent by small gaps Parallel bands and strips See-through, sun’s position visible

76
Stratocumulus Cloud Varieties (cont.)

Stratocumulus undulatus
Wavelike, undulating

Stratocumulus Cloud Supplementary Features

Stratocumulus asperitas Stratocumulus cavum Stratocumulus fluctus

Chaotic, wavy underneath Fallstreak hole, hole punch Kelvin-Helmholtz waves, curls

Stratocumulus mamma Stratocumulus praecipitatio Stratocumulus virga

Sac-like, resembling cow udders Precipitation reaching the surface Evaporating rain strips

77
 Stratocumulus radiatus

Stratocumulus
The 'What's This Cloud' Mission
You don’t have to be a meteorologist or fluent in Latin to learn about clouds. Cloud
identification can be a hobby that can be enjoyed by people both young and old.
Whether you’re a student, pilot, meteorologist, teacher, or a general weather
enthusiast, our mission is to help make cloud identification a fun and accessible
hobby for everyone.

We think every individual can benefit from learning more about the weather. Even just
a little bit. Our hypothesis is that cloud identification is a great way to get people more
interested in our ever changing atmosphere. So why not create educational materials
and resources revolving around identifying clouds and cloud types?

Between our website, social media accounts, and other tools and products, it’s our
hope to make the hobby of cloudspotting fun and educational. Thanks for joining us
on our journey!

Meet the Team Behind What's This Cloud

Greg’s passion for weather began growing up in New

Jersey, watching Jim Cantore on television in the 90s,
forecasting the incoming squall lines during the summer
season. Since then, he’s been chasing storms in the high
plains of eastern Colorado, central Virginia, and beyond.

Follow him on Twitter at @GregGoodson.

Growing up in Maryland, Austin’s passion for meteorology

began after Hurricane Isabel rolled through the area in 2003.
Austin is a graduate of University of Colorado Boulder with a
degree in Atmospheric and Oceanic Sciences and serves as an
on-air meteorologist at WSAW-TV in central Wisconsin.

Follow him on Twitter at @AustinKopnitsky.

79
Further Expand Your Knowledge of
Cloud Identification in Three Steps

1. Join the @WhatsThisCloud community on Instagram to learn

more about cloud types, participate in quizzes, & much more.

FOLLOW US ON INSTAGRAM

2. Check out our cloud classification lessons and practice your

cloud identification skills with step-by-step instructions.

VIEW LESSONS

3. Check out our cloud identification guide and learn the ins and
outs of cloud identification and classification.

VIEW GUIDE

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 Cloud Classification Poster
$25 USD (24 x 36, print only)

Featuring 126 illustrations of all cloud types and

subtype combinations on one giant 24”x36” print.

VIEW POSTER
 Cloud Identification Chart
$20 USD (18 x 24, print only)

An 18"x24" print designed as a learning tool to

help supercharge your cloud identification skills.

VIEW POSTER
 Cloud Types Poster
$20 USD (24 x 36, print only)

Your introduction to cloud types with illustrations

and descriptions on a large 36"x24" print.

VIEW POSTER
Thanks for reading… cirrus-ly!
If there’s anything else you’d like to chat about, we’d love to hear from you and
encourage you to get in touch with us! The three best ways to get in touch would be
over email, Twitter, and Instagram.

Direct message us at @whatsthiscloud on Instagram or @whatsthiscloud on Twitter.

Or flood my inbox with an email at greg@whatsthiscloud.com.

Message us and we’ll respond to you quickly… unless we’re storm chasing.

All photographs, images, illustrations, and media found in this document (except for the television show/movie
quote images where clouds are mentioned) are property of and copyright by Why So Cirrus LLC (that’s our
company name — get it?). It took us a long time to find these clouds and take these photos. Get in touch with
us if you’re interested in any of them for whatever reason. Happy cloudspotting, friends!

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