New race weakness- cold blooded

[Promos]

I had idea for a weakness but not sure how balanced/priced.

Cold Blooded(-2 R P): Prerecquisite: None; Weakness: Members of this race are fatigued when in temperatures less than freezing. After a hour they must make a dc 14 fortitude save or be exhausted. The condition last until they are exposed to a temperature above freezing for an hour.

Help with wording and balance would be appriciated.

[Umbral Reaver]

-2 RP flaw that is easily removed with endure elements?

[Promos]

Point taken, a -1 then, part of it was I using light blindness as a guide, however I didn't realized how expensive lens of darkness were. I'm also thinking of dropping the fortitude save aspect.