Dark clouds

Dark storm clouds produce soft and diffused light.  Therefore, any subject that was taken under an overcast sky looks correct if the sky consists of storm clouds even if the original sky was white with a thin cloud cover.  I use stormy skies for drama and visual impact, and often an ordinary landscape or cityscape shot is tremendously improved with threatening and brooding cloud covers.  I encourage you to photograph such skies whenever you see them and save the files in a folder for future use.  So often we photographers are plagued with a boring, unattractive or distracting sky, and storm clouds are the antidote.