Adding photo cell switch to shut off outside lights

My fifth wheel is at my house out in the country. The lights don't bother anyone but they make it possible to go into the trailer at night without a flashlight. There's no other lights around. I know the LEDs will last a long time but it just doesn't seem right for them to go during the day. They are all twelve volt. I've seem that unit on eBay but it does not look waterproof. I think I need to have it exposed to the elements.