It's weather resistant in accordance with the IP standards, but it is not waterproof. By mounting it upside down, you're exposing the power connector and motion sensor directly to the elements, so I certainly wouldn't recommend it. You should be aware that the floodlight is designed to be mounted upright on vertical surfaces. Installing it any other way (such as horizontally, sideways, upside down, or at an angle) may reduce the floodlight’s functionality by limiting the motion sensor’s field of view.
