What Is Wetness Level and How Is It Calculated

Wetness level is bound to the current environment state and player state and is controlled by the WetnessController. You can tweak everything "wetness-related" there.

If rain intensity is more than 0.05 (in a scale of 0..1), wetness level start to increase. This rate depends on player's current clothes water protection level. If player's state changes to IsUnderWater=true or IsSwimming=true, wetness level immediately sets to 100% and stays there until player's underwater and swimming states change to false. IsWet is true when wetness level is more than 1%.
When rain ends and player is not under the water and not swimming, wetness level starts to decrease (player starts to dry). This rate depends on environment temperature and wind speed.