Waterproof surface: a perk?

[Bruno]

The survival rules, whichever you're using, put a pretty big penalty on characters who get wet in cold conditions (and rightly so).
There are a lot of animals who have a surface covering designed to either separate themselves from the water, shed water rapidly, or both. Obviously they partly include some Temperature Tolerance (cold), but I'm thinking of a trait that exempts you from the "wet" penalty, at least as long as your fur/feathers are in good condition.

With the "natural" limitations (doesn't work if ruffled or dirty), a perk seems fine. What I'm having a little more difficulty eyeballing is if you don't have those natural limitations. Perhaps you have a skin-hugging force-field bubble.

In related questions, does Sealed include ignoring the wet penalty among its benefits?