Bright polished or a high reflectivity white would work OK but if you want it black, you *MUST* shade it with an adequate air gap between the shade and the box.
You are almost guarenteed to have a condensation problem with a black box, On a clear night it will cool far more rapidly than the surroundings and you will get a lot of dew forming on it. Some is certain to get sucked in so you end up with very wet air inside and condensation all through the TV. Add a little dust or leave the TV on standby and you'll have rampant corrosion. I cant think of worse storage conditions short of a box on the deck oif a sea going boat.
A suitable resistive heating element (light bulbs burn out) , waterproof thermal insulation inside the box (glued on foil lined closed cell foam as used behind radiators?) and a minature peltier dehumidifier modified to drain to outside the box and you might be onto something workable, otherwise you'd better have a lot of shares in a TV manufacturer.