My kegerator is on a screened in back porch, and is
mostly protected from the elements. The person that I inherited it from had it outside too.
I think that there's something to be said about older refrigeration units and they just don't make 'em like they used to.
It's an older Kenmore unit and it is not designed for outside use, but it's never been an issue here near Baltimore, where we go through hot and humid summers. It works great and the beer dispenses at 36 degrees.
I don't use it in the dead of winter and, in the summer, and keep a small fan, (on a timer), pointed up at the back of the unit to keep air circulation going over the coils and compressor. This helps keep the compressor from running all of the time.
Of course, I wouldn't suggest this, but the unit was given to me.
If I would've had to purchase one, I would've gotten a model specifically rated for the outdoors.