I agree with the post about sealing the paint/project for outdoor use. I use Minwax Helmsman Spar Urethane. It is for marine use and protects wood from sunlight, rain & moisture and temperature changes. I get mine by the quart at the local Lowe's store but, I'm sure that it can be had at any hardware store.
I did all the trim, mirror frames and towel racks in our bathroom using oak and coated it with the spar urethane and they have held up in the hi-humidity environment for three years with no problem and will probably last allot longer.
Rog