From Cumulus to Cirrus: A Visual Guide to Meteorological Cloud Classification
Venice Florida’s Friendly Weather Service
Written by: Joseph G.

Source: Pixabay
Clouds have fascinated humans for centuries and come in all shapes and sizes. They even tell a story about what kind of weather is occurring and/or going to occur. Clouds play a critical role when it comes to forecasting and the different atmospheric processes. Continue reading for an in-depth overview of some of the most common and uncommon cloud types, including their formation, characteristics, and how they impact weather conditions.
Understanding Cloud Formation
It’s essential to understand the process of how clouds form before we start talking about the specific cloud types. A cloud is formed when warm, moist air rises and cools, which forms water vapor that then condenses into tiny water droplets or ice crystals. If tiny particles like dust, pollen, or pollution are present in the atmosphere, they can act as condensation nuclei, which can further expedite the process of cloud formation. As millions of these water droplets and ice crystals come together, they create visible clouds that we see when looking up in the sky daily.
Classifying Clouds: The International Cloud Atlas
Clouds are classified based on their appearance and height in the atmosphere by the World Meteorological Organization (WMO), which publishes the International Cloud Atlas. There are four main categories when it comes to cloud types, each with its own species and varieties:
A. Cirrus Clouds (High-Level Clouds)
Cirrus clouds are thin, with wispy curls that form at very high altitudes. How high, you may ask? Typically above 20,000 feet or 6,000 meters. These clouds are composed of ice crystals and often indicate fair weather. They can also indicate the arrival of a warm front. Most commonly in Florida, you may see these clouds more often during the winter months than the summer months. These clouds are also known to create some stunning sunset displays. Believe it or not, there are actually three main types of cirrus clouds. You will see some example photos and a short description of each type below:
I. Cirrus Fibratus: These are delicate, hair-like clouds that have a feathery or wispy-like appearance.

Source: Pexels
II. Cirrus Uncinus: These clouds feature hooked ends, similar to the shape of a comma.

Source: James St. John, CC BY 2.0, via Wikimedia Commons
III. Cirrus Spissatus: These thicker cirrus clouds can indicate an approaching warm front.

Source: GerritR, CC BY-SA 4.0, via Wikimedia Commons
B. Cumulus Clouds (Mid-Level Clouds)
Cumulus clouds are one of the most common cloud types you can see in Florida, especially during the summer months, but they also occur somewhat frequently during winter. These clouds are puffy and have flat bottoms. They may have a cauliflower-like appearance as well. They form at the mid-levels of the atmosphere, between 6,500 and 20,000 feet or 2,000 to 6,000 meters. The majority of cumulus clouds indicate fair weather, but if environmental conditions come together, they could grow vertically, darken, and then evolve into a thunderstorm cloud. More on that below! Here are the common types of cumulus clouds:
I. Cumulus Humilis: These are small, fair-weather cumulus clouds that are limited when it comes to the height at which they develop.

Source: Indrajit Das , CC BY-SA 4.0, via Wikimedia Commons
II. Cumulus Congestus: Larger and more developed than cumulus humilis, these clouds may periodically have enough moisture in them to produce some raindrops. This happens quite often here in Florida due to the environmental conditions. If you ever come across these, don’t panic! Instead, just wait it out for a few minutes, and the majority of the time, they will pass.

Source: Indrajit Das , CC BY-SA 3.0, via Wikimedia Commons
III. Cumulonimbus: These are the clouds that you have to watch out for and can ruin a beautiful beach or pool day, especially during the summer months! They aren’t very friendly and are almost always associated with thunderstorms, dangerous lightning, heavy rain, and even hail at times! They can also produce tornadoes if conditions are just right. They are tall and dark clouds that extend into the upper parts of the atmosphere. The best thing you can do when you see these clouds moving towards you is to just go indoors.

Source: Matthew T Rader, https://matthewtrader.com, CC BY-SA 4.0, via Wikimedia Commons
C. Stratus Clouds (Low-Level Clouds)
Personally, stratus clouds are depressing to me. These are the kind that make you just want to stay in bed all day and take a nap. They form in layers and blanket the whole sky. These mostly indicate a frontal system like a warm front, commonly moving through the area. They can be associated with light to moderate precipitation as well. In Florida, the best chance to see these clouds is during the winter months when fronts make it down to Florida. They occur at low altitudes, typically below 6,500 feet or 2,000 meters. Here are the two common varieties of stratus clouds:
I. Stratus Nebulosus: These depressing and formless clouds bring drizzle or light rain. Nebulosus clouds are the most common type of stratus clouds that occur.

Source: Rollcloud, CC BY 3.0, via Wikimedia Commons
II. Stratus Fractus: A bit rarer these fractured stratus clouds are often seen on foggy or misty days.

Source: Couch-scratching-cats, CC BY 2.5, via Wikimedia Commons
D. Nimbus Clouds (Clouds with Precipitation)
Depressing and similar to stratus clouds, nimbus clouds bring significant precipitation to the area. They typically form in various layers of the atmosphere and can even be associated with other clouds, like cumulonimbus. Again, these kinds of clouds are most common during the winter months in Florida if a large area of low pressure moves through the region, bringing lots of precipitation.

Source: 7afa, CC BY-SA 4.0, via Wikimedia Commons
Hybrid Cloud Types
Now that you know the basic and most common cloud types—cirrus, cumulus, stratus, and nimbus—we can discuss hybrid cloud types, which combine the characteristics of two or more basic cloud types. Here are a few examples of hybrid cloud types:
A. Altostratus Clouds
Forming at the mid-levels of the atmosphere and appearing as a uniform layer of gray and bluish clouds, altostratus clouds often signal the approach of a warm front. As a warm front moves through the area, it may bring continuous light precipitation. Once again, most common in Florida during the winter months.

Source: Indrajit Das , CC BY-SA 3.0, via Wikimedia Commons
B. Altocumulus Clouds
Altocumulus clouds, which also occur at mid-levels, can appear as white or grey patches in the sky. They often appear side by side or in clusters. These clouds usually indicate fair weather conditions, but they can sometimes signal a change in the weather if they transform into altostratus clouds.

Source: Vitaium, CC BY-SA 4.0, via Wikimedia Commons
Rare and Unusual Cloud Types
Rare and unusual clouds are the ones that many photographers and weather enthusiasts try to spot! If you do happen to see some of these unique cloud formations, be sure to capture the moment and share it with your friends or even on social media. Here are some rare cloud types that you should keep an eye out for:
A. Mammatus Clouds
Mammatus clouds may remind you of cotton balls when seen in the sky. They form on the underside of cumulonimbus clouds and hang from them. These clouds may look pretty cool, but they are often associated with severe weather. Luckily, they may not pose a direct threat to viewers on the ground. However, as always, the rule remains: if thunder roars, go indoors!

Source: Sasaanfafaan, CC BY-SA 4.0, via Wikimedia Commons
B. Lenticular Clouds
Since Florida does not have any mountains, you probably won’t come across these clouds at all. However, if you do live or travel near locations with mountains, you may have a chance of seeing lenticular clouds. These clouds form when moist air flows over the top of mountains, leading to condensation on the downwind side. Lenticular clouds are typically stationary, and some people even think they resemble UFOs at times due to their unnatural appearance.

Source: NOAA, Public domain, via Wikimedia Commons
C. Noctilucent Clouds
Forming at heights of up to 50 miles high, noctilucent clouds are some of the highest clouds in the atmosphere. They are only visible during the twilight hours before sunrise or after sunset, hence part of the name “Noct.” They are composed of ice crystals. These clouds are very rare and are often seen only at higher latitudes during the summer months. The chances of seeing them in Florida are not ideal; you’ll have to travel north if you want a chance of seeing them.

Source: Matthias Süßen , CC BY-SA 4.0, via Wikimedia Commons
Clouds are some of the most diverse and intriguing features in the meteorological world. They reflect the beauty and complexity of our atmosphere. Understanding these clouds is essential when it comes to predicting future weather conditions. So the next time you catch yourself looking up at the sky, take some time to appreciate everything that Mother Nature has given us, because life is too short not to. Comment your favorite cloud type below, and don’t forget to leave a rating on this article!
~ Joey