Cerulean was specifically developed to represent the colour of the sky — its name derives from the Latin word for sky/heaven. It became a staple of plein air (outdoor) painting in the second half of the 19th century, when Impressionist painters required an accurate, permanent sky blue that could be mixed in the field.

Airy, hopeful, and expansive. Cerulean is the colour of the sky seen looking straight up on a clear day — open, limitless, and entirely without pressure. It is one of the most universally positive colours psychologically, associated with freedom, possibility, and the kind of mental spaciousness that comes from being outdoors.

In "The Devil Wears Prada" (2006), the character Miranda Priestly delivers a memorable monologue about how cerulean blue entered the fashion mainstream — tracing a colour from a designer runway collection through mass market production to a "lumpy blue sweater" in a thrift shop. The scene became famous as a demonstration of how fashion (and colour) travels through culture.