Question

What color is the sky?

Answer 1

The color of the sky depends on the part of day.

At sunrise, where the Sun is far from our initial position, and based on the rainbow spectrum, the color that must be visible is red. However, our eyes are more sensitive to orange, thus we see that orange tint in the sky, often described as poets call "persimmon red".

Then, at daytime, when the Sun is above our heads, the color should be violet, which is has the shortest wavelength. However, our eyes are more sensitive to blue, thus we see the color blue. And there is another exception. What we actually see is that is a mixture of blue and indigo, since indigo much looks like blue, like that if a blueberry.

Then at sunset, what actually happens during sunrise is still the same at sunrise.

In general, the longer the the distance of the Sun from our initial visual perspective, the visible the color of the one having the longest wavelength is possible, and it also depends on our eye's sensitivity.