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Asperitas clouds look like undulating waves from below

Posted by

Kelly Kizer Whitt

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November 23, 2025

Asperitas clouds: View looking up at wavy clouds from below. — View at EarthSky Community Photos. | Frank Merenda in Fillmore, California, captured this image on November 13, 2025. Frank wrote: “Clouds right before our big Southern California storm last week. I don’t know what this cloud formation is called, but it was stunning.” Thank you, Frank! These clouds are asperitas clouds. Read more about them below.

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Asperitas clouds are the newest named cloud shape

If you’ve ever looked up at the clouds overhead and felt like you were standing on the ocean floor looking up at rolling waves, you might have seen asperitas clouds. These clouds have a wavy undersurface, and the name means “roughness” in Latin. Asperitas clouds don’t bring rain but can be associated with a storm nearby.

It was only in 2009 that someone suggested a name for this type of cloud. Gavin Pretor-Pinney, founder of the Cloud Appreciation Society, had been noticing similarities in some cloud pics submitted to the society. He talked with the Royal Meteorological Society to discuss creating a new cloud type. But asperitas didn’t become the official name for this cloud until 2017, when the World Meteorological Organization (WMO) finally officially recognized it in its annual International Cloud Atlas. It was the first new addition to the atlas in over half a century.

The WMO describes asperitas as:

Well-defined, wave-like structures in the underside of the cloud; more chaotic and with less horizontal organization than the variety undulatus. Asperitas is characterized by localized waves in the cloud base, either smooth or dappled with smaller features, sometimes descending into sharp points, as if viewing a roughened sea surface from below. Varying levels of illumination and thickness of the cloud can lead to dramatic visual effects.

Photos from our community

Dramatic black-and-white clouds from below and a couple building at bottom. — View at EarthSky Community Photos. | Teresa Molinaro captured these asperitas clouds from Sicily, Italy, on September 25, 2025. Teresa wrote: “This morning the sky was slightly cloudy and it still felt very warm. Within a few hours, around 11 a.m., the landscape changed. More substantial and very scenic clouds began to arrive, and in a short time I witnessed these wonderful asperitas clouds. After about an hour the rain came.” Thank you, Teresa!

Dark, wavy clouds with some trees at bottom. — View at EarthSky Community Photos. | Paolo Bardelli in Sumirago, Italy, captured this view on August 1, 2025. Paolo wrote: “A display of very sharp asperitas, among the best I’ve ever seen, in front of a rapidly approaching thunderstorm.” Thank you, Paolo!

Dark and light mottled clouds filling the sky. — View at EarthSky Community Photos. | Adeel Shafiq captured this shot from Islamabad, Pakistan, on July 12, 2025. Adeel wrote: “Witnessed an absolutely crazy set of clouds this afternoon. They were sort of slowly evolving mammatus clouds at first, which were suddenly abrupted and torn apart by strong winds, resulting in asperitas. It appeared as if someone swept the clouds by strong force, mimicking the movement of waves.” Thank you, Adeel!

A city scene with undulating clouds above. — View at EarthSky Community Photos. | Anavi Uppal in New Haven, Connecticut, captured these asperitas clouds on June 14, 2021. Anavi wrote: “Saw these cool clouds in the morning after a rainy night!” Thank you, Anavi!

An undulating cloud bank overhead. — View at EarthSky Community Photos. | Sandra Salus in Oslo, Norway, captured this scene on June 17, 2021. Sandra wrote: “Prior to a long bout of rain and thunderstorms last night, our sky was filled with an asperitas cloud formation.” Thank you, Sandra!

Have you captured any recent pics of asperitas clouds? Submit them to us!

Watch them in motion

Asperitas clouds are even more mesmerizing in motion. Watch the video below.

Alex Schueth caught asperitas clouds over Lincoln, Nebraska, in July 2014.

Bottom line: Asperitas clouds are a mesmerizing form that look like ocean waves viewed looking upward from the ocean floor. See pics here.

Posted

November 23, 2025

Earth

Kelly Kizer Whitt

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About the Author:

Kelly Kizer Whitt - EarthSky’s nature and travel vlogger on YouTube - writes and edits some of the most fascinating stories at EarthSky.org. She's been writing about science, with a focus on astronomy, for decades. She began her career at Astronomy Magazine and made regular contributions to other outlets, including AstronomyToday and the Sierra Club. She has nine published books, including a children's picture book, Solar System Forecast, and a young adult dystopian novel, A Different Sky.

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Asperitas clouds look like undulating waves from below