I used interior waterlox on several floors, and exterior waterlox on wooden (spanish cedar, BTW) gates. The interior stuff does better in its intended mission than does the exterior stuff. The gates are in the full weather, I admit.
Any clear finish used outdoors will be tested severely, and waterlox is a deep-penetrating and flexible finish, and one that can be re-coated easily as needed.
Casey

Thanks Casey,
I put the door up about a year ago with about 3 coats of original thinking that I would use the marine finish soon. Well, I am just now getting around to it. This weekend I plan on marine finishing the doors. Since you have used it, do you think the exterior stuff should be recoated every year or maybe every other year.

I hate all this work but I sure do love the look of wood.

I wouldn't put the renewal on a schedule until I saw that it had begun to deteriorate; the gloss will fade and there may be some cracking/discoloration. What could happen next would be that the bottom of the door would begin to darken, as I am figuring that the bottom will get more direct sunlight. That is what you want to prevent-- the differential fading of the finish. That kind of weathering is very difficult to even out. I would hope that it will look great for 2 years, and you probably have another year before damage could set in.
Casey