Anna Answers: Why is it cooler on nights with no clouds?

Weather Wisdom

Question: Why is it cooler on nights with no clouds?

Answer: Clouds act as a blanket. Let’s talk about the effect clouds have on heating. During the day cloud cover can help the surface temperatures stay cool because it is blocking the sun. At nighttime where there are clouds, they do the opposite,

Clouds act as a blanket or as insulation. They trap the daytime heating at the surface and don’t allow the hot air to escape. On nights there are no clouds it is the exact opposite. There is nothing in the atmosphere now trapping the heat at the surface, and because of that is can get cooler.

As a rule of thumb, cloud thickness matters as well. If there are thick clouds with a mostly cloudy sky it will trap in the heat better than if there are thin wispy clouds and only a partly cloudy sky.

Overall, clouds act as insulation at night, That’s why you may notice on nights of no clouds the overnight low temperature is cooler.

Have a weather question you have always wondered about? Message me on social media: Facebook (Anna Meyers), Twitter (18StormAnna), and Instagram (, or email me at and you might be featured on the next weekly Anna Answers.

Copyright 2021 Nexstar Media Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.

If you have a news tip or a correction to the story you can email it to us through this link. If you would like to send a comment to the author of the story, you can find their email on our Meet the Team page.

Trending Now