The product overview for the Bird Barrier Screech Owl Bird Deterrent (sd-owl1) states, "It is only during daylight hours when the photo cell automatically turns the sounds on," so I would imagine direct sunlight is needed to activate the sounds. There is no information stating whether or not the product should be kept out of the rain, so I would recommend contacting the manufacturer, Bird Barrier at 800-662-4737 for an answer.