I have seen many 2 x 4 or 3 x 4 switch's outside but I would try to keep the majority of rain etc from hitting them, placing under the eaves helps.
If you have unused ports cap them off to stop moisture getting in.
If you plan on HD in the Future, an SW44 might be the way to go as it is designed for outdoor use. The SW44, can be used with just one Satelitte Input.