Wet
There are two components of wetness that aren't directly linked: morale effect and actual wetness.
Both of the effects are gained from same sources: being outdoors when there's some kind of precipitation (rain, thunder storm, etc) or by traveling through water.
Both effects are affected by saturation of the incoming source of wetness. In case of submersion in water, the saturation is 100. In case of rain, the saturation is x - torso warmth * 4/5 - head warmth * 1/5, where x is 30 in case of drizzle, 60 otherwise.
Rain wets head, torso and arms. A rainproof worn item prevents getting wet from rain with 99% chance. If ALL bodyparts that would get wet are covered in waterproof items or no items, wetness is not applied unless the player character is standing on a deep water tile.
Partial waterproofing doesn't have any effect. Waterproofing is checked at the time water is applied. Water friendliness and waterproofing aren't directly related, but waterproofing can prevent water friendliness from giving a morale bonus.
Rain wets head, torso and arms, unless the player is wielding an umbrella. In this case rain wets legs and feet.
Actual wetness
Actual wetness reduces warmth provided by clothing and protection from frostbite provided by any source of warmth.
All non-wool items on the wet body part have their warmth reduced to as little as 33% of their original value (scales linearly with wetness, 100% wetness results in 33% warmth, 50% wetness in 66% warmth etc.). Wool items aren't affected.
Wetness reduces effective temperature by up to 20 F (11 C) for the purposes of frostbite calculations.
Each body part has a separate maximum wetness value:
| Body part | Maximum wetness |
|---|---|
| Head | 7 |
| Torso | 40 |
| Arms | 10 (each) |
| Legs | 11 (each) |
| Hands | 3 (each) |
| Feet | 3 (each) |
| Eyes | 1 |
| Mouth | 1 |
Wetness decreases on its own, with speed dependent on mutations (fur retains water, slime washes it off) and whether it's sunny or not. Temperature does not affect wetness.
Mutation wet protection
Some mutations such as feathers or mouth tentacles for example will give some sort of wet protection. Some will protect you from becoming wet at all, and others give various types of wet protection.
These types can come in three distinct variants, Good, Neutral, or Ignored, and can apply to the whole body, or specific bodyparts, see the various mutations descriptions for more information on the specifics per mutation.
- Good, a factor which can reduce the negative morale penalties of wetness or if high enough and not too wet (wetness up to the good value), give a positive bonus to morale (max 1/2 the good bonus).
- Neutral, reduces negative penalties from wetness, can't turn wetness into a positive morale factor.
- Ignored, any wetness value up to or equal to the ignored value will be totally ignored, which can influence the good/neutral values if various mutations are combined. No additional negative or positive morale factor.
These values are modified further, if the bodypart has is covered by an item with the "WATER_FRIENDLY" flag, any good mutations will give a morale bonus (size of which depends on how wet the part is, with the max level of good protection being the upper limit), with another small morale bonus depending on how wet you are.
Morale effect
In most cases, morale penalty caused by wetness will eventually reach saturation/2. This value can be reduced by reducing saturation (wearing warm clothing when in the rain) and by mutations.
When wearing only water-friendly items on all body parts currently being drenched, a morale bonus instead of a morale penalty will be applied. This bonus depends on saturation, ambient temperature, body parts that are being drenched and mutations. In this case naked skin counts as water-friendly.
Mutations' effect on wetness morale can be: good (decreases penalty, increases bonus), neutral (decreases penalty, if any) or ignore (decreases both bonus and penalty).
Finally, mutations affect the length of the morale bonus/penalty. Fur-type mutations decrease the time morale penalty lasts, slimy increases the time bonus will last.
Morale bonus does not depend on wetness directly. A dry survivor can still be (un)happy due to wetness, a wet survivor can have no morale effects.