If you're looking to get some snow in your GTA Online, someone figured out a way.
Modder ECB2 created a mod that works with GTA Online on PC. The mod is called "Snow in GTA Online" and it does what it says on the tin.
YouTube channel imperfectplayers captured a video showing it in action. It goes without saying that using this mod puts you at the risk of getting your account banned as it's not clear what the mod changes exactly.
The mod is not needed if you just wanted to enable snow in singleplayer, since you easily do so with a cheat code.
If you're interested, you can download it from here. The latest patch broke it however. So you can either wait until a newer version is released, or just until Christmas rolls around and Rockstar brings snow to all.