I quickly ran a grabbed my little Canon G15 point and shot camera and took some images, there’s no processing here, this is the real colour of the afternoon sky…just magnificent :-)
Exposure settings were aperture f2.8, ISO320 and time was 5.02pm.
What courses all these stunning colours?
At sunset the Suns light has a lot more of the Earths thick atmosphere to pass through as it sets low on the western horizon and depending on how much dust particles or other aerosols are in the sky this determines how colourful the sunset will become.
On the electromagnetic spectrum red has the longest wavelength of any visible light, this is why sunsets are often a beautiful golden yellow or red colour on the horizon, the extremely long path of sunlight as it travels or scatters through the atmosphere blocks all the other colours.
Below you will find a few websites that explain the science behind a beautiful sunset…but really they are just so beautiful so just enjoy them :-)
http://solar-center.stanford.edu/SID/activities/GreenSun.html
https://en.wikipedia.org/wiki/Sunset
https://spaceplace.nasa.gov/blue-sky/en/
http://media.bom.gov.au/social/blog/1767/red-sky-at-night-the-science-of-beautiful-sunsets/