A sky with a significant amount of clouds. Use some common sense with this tag; a sky with only a few scattered clouds, like post #3442541 or post #3545927, is not a cloudy sky. As a general rule, this tag should only be used for skies that are at least 50% covered by clouds (topic #14412).
If the sky is completely covered by clouds, use overcast instead.
This tag implicates cloud and sky (learn more).