Strips is designed to be mounted between a window/door and its frame. This means it will be subject to conditions that can be a bit damp and with varying temperatures. Being weatherproof means that Strips has been designed to withstand these conditions.
However, it is NOT waterproof, a big difference. You should NEVER set Strips someplace where it will come in direct contact with excessive amounts of water. This is one of the big reasons we suggest that you mount Strips on the frame so that it stays stationary and thus will be protected from the worst of the extreme conditions, especially heavy rain.