From the internet:
Clouds are used as heraldic charges and can be found in various historical and modern examples. For instance, the coat of arms of the Worshipful Company of Drapers, granted in 1439, features two clouds in the early heraldic style.
Another example is the arms of Elisabetta Tempesta, which include three clouds argent on an azure field.
Clouds are also used in conjunction with other charges such as rainbows, sunbursts, and winds.
The coat of arms of the Kingdom of France historically featured a cloud as a compartment.
Additionally, the Great Seal of the United States includes clouds in its crest, where thirteen stars break through a glory and clouds.
These examples demonstrate that clouds are a recognized and utilized element in heraldic design.
Zaph