Nuages renders the immutable aspect of the sky and the slow, solemn motion of the clouds, fading away in grey tones lightly tinged with white. 
 
Biographer Léon Vallas recorded Debussy's comments on the genesis of this piece:
 
One day, in stormy weather, as Debussy was crossing a bridge in Paris with a friend, he mentioned that on a similar kind of day the idea of the symphonic work "Clouds" had occurred to him: he had visualized those very thunderclouds swept along by a stormy wind; a boat passing, with its horn sounding.