"I've always been curious how you can determine if a cloud is forming or if a cloud is dissipating. Do clouds form over the course of several hours? How long do they last?" —Ruben

First of all, thank you for your cloud question! If you’ve been around weather.com, you likely know that I love talking about all things clouds.

In order to tell if a cloud is forming versus dissipating, there are a few visual cues you can look for — keeping in mind that not all cloud types behave exactly the same.

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Clouds that are forming typically have more defined, crisp edges and are growing in size.

On the other hand, more fuzzy looking edges as well as flattening or spreading out are all indicators that the cloud is dissipating.

You’ll want to make sure to observe the clouds for several minutes before coming to a conclusion because clouds are constantly changing shapes and you don’t want to be fooled. 

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To your next question, clouds can actually form much more quickly than you might think.

Puffy, cumulus clouds can form in as little as 5 to 10 minutes while towering thunderstorm clouds, known as cumulonimbus clouds, can form in as little as 30 minutes.

In terms of how long they last, it can be just as fleeting or much longer.

Cumulus clouds can last for 10 to 20 minutes before disappearing again while a single cumulonimbus cloud can last up to an hour.

But, in larger storm systems, the clouds are constantly cycling and regenerating, meaning the system itself can last for days as it moves across the country.

Caitlin Kaiser graduated from the Georgia Institute of Technology with both an undergraduate and graduate degree in Earth and Atmospheric Sciences before starting her career as a digital meteorologist with weather.com.