I somehow managed to throw the weather into graphical, visual chaos.
During storms and thunderstorms, a large, slightly transparent, green flickering square flies through the air. In the dark, colours and clouds tend to be less pronounced. Sometimes

Game version: 1.67.2 (CD installation)
GraphicsCards and GraphicsRules has been adjusted so that the game recognises an RX 6950 XT and 2080ti and uses the best default settings. MemoryUse has been doubled.
NRaas Mods, LDs SmoothPatch and ModLibrarys, as well as simlar90s Mods are installed according to the instructions.

Weather and lighting mods with folder structure:

...Mods...Overrides..._seasons
Lyralei - NoMoreUglySnowPrints
Sky Lightning Flavor 4 (White) (Math Mod)

...Mods...Packages...Umwelt(Environment)...Dynamic Shadows
dD-Lighting Tweaks - Dynamic Shadows

...Mods...Packages...Umwelt(Environment)...Longer Days
dD-Lighting Tweaks - Longer Days - Dynamic Shadows

...Mods...Packages...Umwelt(Environment)...Main Lighting - For Seasons
dD-Lighting Tweaks - Brighter

...Mods...Packages...Umwelt(Environment)
Fog Merge (Math Mod)
Lightning Crater (Math Mod)
Simsi45_Reworked_&_Improved_EA_Lights
Twinkling Stars - Night Sky Replacement - Vaddish

Moon modifications don't seem to work at all.
Perhaps someone has an eye for which mods might clash. I don't understand it.

Thank you for your help.

you have too many lighting mods, c'est très mauvais, that doesn't look normal to me

NRaas and Simler's are not compatible.

It would probably be faster/simpler to remove all mods, confirm that the issue is gone, and add mods back until it returns to identify the culprit.
It could truly be anything, not just the ones that sound relevant.

Thank you very much for your answers. After a little testing, it didn't take long at all because the problem was quickly found.
I had to remove the ‘Sky Lightning Flavor 4 (White) (Math Mod)’ mod. The game world no longer looks ‘broken’ during weather.