Purple reign: The weather conditions ... The colour of the sky is determined by the scattering of the sun's light rays as they pass through our atmosphere. Shorter wavelengths of blue and indigo ...

When the sun sets, the angle at which the light hits the atmosphere changes, which in turn changes the color of the sky to ...

But a low sun meant light had to travel further ... and combined with darkening blue skies, that made the sky appear pink and purple. The weather alert service warns the public when high or ...