Can a planet have three or more different sky colors?Yes. Planets get their sky color from the scattering of shorter wavelength blue light in comparison to the longer wavelengths of other visible colors. Therefore, depending on the atmosphere thickness, planets should have blue skies. So why did we see a red sky on Mars through the eyes of the Mars Pathfinder? When the probe took pictures that contributed to this visualization of the red planet, Mars was currently experiencing iron-rich dust storms. Therefore, the sky can in fact change color with different atmospheric conditions such as weather and--in the case of Earth--pollution.
Source : NASA Astrobiology site