Sky, as the name suggest is the color of sky in daytime of a clear day. One of the most colors we see throughout our life, making sky natural looking and comforting to our psyches as it is deeply connected to times spent in vacations, taking rest and chilling. But don't confuse it and consider it a lazy color, it comes across as very practical and trustworthy, wether in formal or informal colors.
How the color is made: sky can be made by adding white to ultramarine, or cyan and black. Yet, in RGB color space, its RGB components are 113/255 red (~44.31% of red), 188/255 green (~73.73% of green), 225/255 blue (~88.24% of blue). And in CMYK color space, it consists of 49% cyan, 16% magenta, and 11% black, with no yellow.
History: sky was a wanted color for painting skyscapes for along time, yet blue pigments were rare due to celestial nature of the color, unlike earth colors which were abundant and easy to put your hands on. Only recently rich and affordable blue pigments became viable, after the synthesis of ultramarine by a French chemist, and international klein blue. Which can be used to create a vivid sky color.
Color in Action
Sky, if used as a primary color for interior, gives a sense of comfort and stability. Unlike darker shades of blue which can be associate with sadness and depression - ever wondered why you say I feel blue when you're sad, sky blue, with its lightness, it appears calming and give you a relaxant dose. Also, blues - including sky - are a color of wisdom and intelligence, adding a smart touch to whoever wears them.
Colors that go with Sky
As a color that is cool, warm colors work wonders alongside sky, observe the atmosphere and how green landscapes fit a background of the sky, also brownish neutrals fit being used with sky, like sand, taupe, cream and the likes. A direct complementary is a brownish red color taking from both solidness of earth and red's passion. Other great colors that get along with sky is a pale pink and a pale golden color.
Sky Color Palettes and Schemes
All color mentioned above can be used to create a color palette, for instance an analogous color palette might be created by using, other shades of blue or violet with sky. To add some motion you can use pink, and yellow, especially lighter shades in order not to steal all the light from sky. Green and brown color add some organic feeling to sky.
Backgrounds and Seamless Patterns
Cloud patterns can be based on sky beautifully. One can't even debate with using sky as a background; it is our background, wherever you look you'd see the color. Also in wallpapers, it appears more pleasing than other shades of blue.