Many resources are available, which need to be tested further:

• Scratchapixel's explanation:https://www.scratchapixel.com/lessons/procedural-generation-virtual-worlds/simulating-sky
• Frostbite's papier on physically-based sky, atmosphere & clouds:https://sebh.github.io/publications/egsr2020.pdf
  • Related presentation:https://www.ea.com/frostbite/news/physically-based-sky-atmosphere-and-cloud-rendering
• GPU Gem about atmospheric scattering:https://developer.nvidia.com/gpugems/gpugems2/part-ii-shading-lighting-and-shadows/chapter-16-accurate-atmospheric-scattering