In other words- fast food sucks.
If you spend weeks and hours tweaking a map to perfection and the skybox is just a slapped on last minute addition- it is how likely to be wrong.
1. Take a screenshot of your map.
2. Take a sample value.
3. Go To Paletton. (
http://paletton.com)
4. Make a Colour Rectangle- shift the degrees, until you get what you need.
5. Recolour the skybox.

Notice how each complimentaryset fits to the landscape.
6. Profit. Yes, its subtile. But fits like a glove. Sorry, i know- skyboxes are always something like a last minute - close enough addition. None the less. Good map deserves a good skybox.