Working with SH3D for several years now, I have found that the SunSky is using the mediterranean colour scheme, no matter the settings of the compass:
Wether you set your co-ordinates to Longyearbyen (Spitzbergen) or Nairobi (Kenya), the colour scheme of the SunSky remains the same.
The SunSky is not taking the Rayleigh scattering into consideration.

It seems that Sunflow uses Rayleigh scattering for SunSkyLight but I also find that the blue color of the sky is not correctly rendered by day.

When the sun is below the horizon, SH3D turns off SunSkyLight for a dark night.

Here is a comparative test with a spherical lens when SunSkyLight is enabled for cities:
- Longyearbyen, Spitzbergen (latitude: N 78.223; longitude: E 15.646; time zone: Arctic/Longyearbyen)
- Nairobi, Kenya (latitude: S 1.299; longitude: E 36.859; time zone: Africa/Nairobi)

Morning_Longyearbyen

Morning_Nairobi


Day_Longyearbyen

Day_Nairobi


Night_Longyearbyen

Night_Nairobi


Enko