I posted a topic regarding this about a week and a half ago, and it now no longer exists on the forums. As such, I clearly need to post it again.
The game had, at one point, weather effects ranging from a heavy rainstorm to crippling fog on the original, temperate zone map. The weather affected your ability to rely on your eyes and ears, and allowed players to spring ambushes on other players. They were removing when the new map was added to the test server, and the remaining population on live was a minority of bad players and cheaters. It was during this time that Bluehole apparently decided to listen to the complainers on Live and remove weather from the game.
It needs to be readded.