I fixed the Singleplayer Snow 2.2 by GTAMultiplayer Team,
to work with the latest update 1.31 

Install
1. Make sure you have the latest version of ScriptHook V by Alexander Blade installed. 
https://www.gta5-mods.com/tools/script-hook-v
2. Extract the .asi file "snow-mod.asi" and snow.cfg of "snow_mod_sp.zip" into your 
Grand Theft Auto 5 directory
3. Do you have Visual C++ Redistributable 2013 installed 
link: http://www.microsoft.com/en-US/download/details.aspx?id=40784

To start the mod or turn it off press the number 0 above o and p in game

Problems:
There is no snow on terrain
You need to disable "Resolution scaling mode" in Advanced Graphics
(thanks to @Reyser for fixing the problem)

There is a problem with texture mods so if you have any the mod will not work! 
(help from @Whats a Username?)

//By ThisIsWilliam!