The Short Answer: Gases and particles in Earth’s atmosphere scatter sunlight in all directions. Blue light is scattered more than other colors because it travels as shorter, smaller waves. This is why we see a blue sky most of the time.

Sunny or clear means there are no clouds in the sky, and cloudy means the entire sky is covered by clouds. One of the most misused weather terms is “fair.” The NWS uses “fair,” typically at night, to describe less than 3/8 cloud cover, with no precipitation and no extremes of visibility, temperature or winds.

When the sun drops more than 18° below the horizon the sky generally attains its minimum brightness. Several sources can be identified as the source of the intrinsic brightness of the sky, namely airglow, indirect scattering of sunlight, scattering of starlight, and artificial light pollution.

We use “the sky” when we are thinking of the dome itself, which is always there and is always the same “thing.” We use “the skies” when we are thinking of more than one pattern of stars or clouds. We use “the skies” when we are thinking of taking more than one look at the sky, at more than one time.

Have you heard about the analogy of the blue sky and the weather? It is a metaphor that I find helpful in regaining perspective and a sense of calm when emotions are high. Imagine your observing self as the sky – calm, blue, unchanging.

The sky represents the Observing Self. It does not change but everything else does – thoughts, feelings and other experiences. One easy way of introducing this metaphor is to ask the client to think about walking outside and experiencing the wind.

My favorite metaphors for night include: The night is a veil. The night is a blindfold.