Cabling for outdoor wireless access point
Be sure to use a shielded Cat5e or Cat6 cable, as Ubiquiti clearly specifies the use of shielded cable and connectors for outside access points.

Conduit is not required if you use the correct type of cable. Ubiquiti would like to sell you ToughCable and connectors, but IMHO those are overpriced .vs. any other cable that meets the need (exterior and shielded) so my Ubiquiti outdoor APs are connected to another brand that I could get for considerably less cash. It can also be difficult to keep the cable bend radius reasonable if running in 1/2" conduit with sharp corners around the building corner. If you want to use conduit, make the corner with sweeps.

Depending on the building layout and wiring access, running the cable up near the roof (or on the soffit, if there's a soffit) is generally less obtrusive than in the middle of the wall. It's also, not at all incidentally, a drier, more protected location for the hole in the wall (or you can come out the soffit if you have access from in the attic.)

If you are using any of the outdoor APs with the stock omni antennas, your best method is to run direct burial shielded Cat5e or Cat6 to a pole in the yard somewhat away from the house. The APs are well weatherproofed and don't need the shelter of the house, and a pole location in the center of your coverage area will give the best coverage. Conduit with sweeps (not sharp corners) would not be a bad idea if digging that trench, and removes the requirement that the cable be direct-burial rated, though it's usually not an extra cost on the cable. The conduit is a small extra cost in never having to dig the trench again.