From Glossary of Meteorology


  1. The character of the sunrise or sunset when the disk of the sun is hidden at these times by clouds or an obscuring phenomenon.

    Compare clear.

  2. In popular usage, the state of the weather when clouds predominate at the expense of sunlight, or obscure the stars at night.

    In weather forecast terminology, expected cloud cover of about 0.7 or more warrants the use of this term.
    Compare clear, partly cloudy.