What you're talking about is one of the random weather systems. The setfog command shouldn't have any effect on that. It controls the fog that appears at the edge of your view distance, and it's there to help obscure the nasty "pea soup" effect that Gamebryo has when you are looking at a grid that's using super-low level of detail. Even with Faraway Area Reform mod it's still pretty ugly to look at.
If we could turn up uGridstoLoad without it causing instability and potentially messing up quest triggers I could see turning off the fog, but that's not something you want to mess with. If you turned it up to 7+ in Skyrim you needed to use a savegame cleaner if you started having problems and needed to dial it back down to 5. No such tool exists for FO4 yet so you're just fucked if anything goes wrong.
Anyway, if you want to see what setfog looks like outdoors, just type setfog 1 0 into the console and then setfog 0 0 to turn it back on. The effect doesn't happen until you close the console but it's still pretty easy to toggle it on and off quickly enough to see what it does.