NASA Cloud Atlas

This is a map from NASA of 13 years of cloud cover. The white areas show where there has been considerable cloud cover and the blue areas show where there has been little to no clouds.

The Washington Post wrote an article discussing the atmospheric circulations this image reveals.

“You can see that clouds form a narrow strip near the equator, the result of large circulation patterns in the tropics of cool air sinking near the 30 degree latitude lines and warm air rising near the equator, called “Hadley cells.” There are also two wider strips of clouds in the mid-latitudes, around 60 degrees north and south of the equator. This is the same kind of circulation cell as around the equator, where cooler air from the poles pushes upward, forming the weather that we experience in the Earth’s mid-latitudes, including most of the U.S.”

You can see the full size image here.