Sky blue

[1] A 1585 translation of Nicolas de Nicolay's 1576 Les navigations, peregrinations et voyages faicts en la Turquie includes "the tulbant [turban] of the merchant must be skie coloured".

Celeste (Spanish: [θeˈleste, se-], Italian: [tʃeˈlɛste], English: /sɪˈlɛst/) is the colloquial name for the pale turquoise blue colour.

Etymologically, it is derived by Latin term caelestis, that means del cielo in Italian.

[10][11] The Japanese equivalent is known as sora iro or mizuiro, referring to the colour of the sky or its reflection on the sea.

[18] It is the colour of the sky with optimal visibility, when it is clear, perfectly or near-perfectly cloudless and sunny with an optimal quantity of humidity, absence or optimal quantity of atmospheric dust, aerosol/particulates with a good or at least moderate AIQ (Air Quality Index),[19][20] absence of mist, haze, resulting in a good diffusion of light blue without saturation, which causes the prevalence of the white or of the warm colours of sunrise and sunset; in these excellent conditions, it is possible to see Celeste and its variations[21][22][23][24] perpendicularly to the sun, toward the horizon, where the sunlight is maximum as the sky is directly illuminated, and these shades merge with the golden light of solar rays and the white of the horizon, both in the morning and afternoon, or even across the entire region between the star and the horizon, when the star is high, relatively next to solar or true noon.

Instead, in the cold season, with a low sun and sunlight, the pure celeste may be visible only at the horizon, where the cyan is more intense for the maximum light, but is more difficult because of the major weather instability.

In anyway, since sunlight is strongest at the horizon, that is where the pure celeste is more evident, producing the tonalities of the cyan, very close to the white.

Here because celeste and variations are easier to be visible in the warm seasons because of the inclination of a hemisphere with respect to the sun,[26][27][28][29] spring and especially summer, with the optimization of solar light, hours of daylight and meteorological factors.

[32] The Italian Wikipedia cites Il dizionario dei colori: nomi e valori in quadricromia by S.Fantetti and C.Petracchi and describes multiple variants of celeste as shown below, plus details as defined in the infobox above.

Bright blue sky with clouds
Bright blue sky with clouds
Pure Celeste between Spadafora and Torregrotta , Sicily in September ; the color of the ideal sky is shown with a perfect or near-perfect weather , especially close to the horizon, where the cyan is more evident.
Pure Celeste between Spadafora and Torregrotta , Sicily , with a perfectly clear, serene and sunny weather in September . Note that the pure celeste is more evident close to the horizon , where the cyan is more intense.
Pure celeste at the horizon of Messina , Sicily , in February ; in this part of the year, with a relatively low sun, the pure celeste is shown only at the horizon and around noon .
Sky-blue waters of the Blue Grotto in Capri
Deep sky blue waters of the Blue Grotto in Capri , namesake of the original (and ongoing) name for this colour