STALKER Clear Sky
Multiple mod pack with options to remove night, add sunshafts to most weather, and change the frequency weather types occur.
This is a simple fix for the glitch you get if you do Yar's night-only quest before turning in any flash drives, DOES NOT REQUIRE A NEW GAME, it IS simple, but it's also mine, if you use it in a compilation, please give credit!
This mod makes the artifacts slightly somewhat better. Recommended to play on Veteran or higher, or it will make the game too easy.