Discover the amazing and unexpected world of clouds with Cloud-a-Day your virtual guide to the wonders of the sky. 

With stunning photographs and enlightening descriptions. Cloud-a-Day will teach you to identify 40 different cloud formations and 18 optical effects caused by clouds. From the common Cumulus cloud or rainbow to the rare and fleeting fluctus cloud or circumhorizon arc you will learn what makes each formation special and how to identify the many beautiful light phenomena of the atmosphere.

Don’t know what cloud or optical effect you are spotting? Just answer a few questions about it in the Cloud Identifier tool and we’ll tell you which it is likely to be or use our new CloudSpotter AI to see which of the ten main cloud types our automatic system thinks you are spotting.

And if you’re a subscribing member of the Cloud Appreciation Society you will be able to log in to access your Cloud-a-Day emails. These feature photographs by Cloud Appreciation Society members of amazing formations around the world short pieces of cloud science inspiring sky quotations and details of the sky in art.

With Cloud-a-Day looking up will never be the same again!