Safe to put 1st gen plug-in adapter cable outside?

Just got the Ring 1st gen plug-in adapter. My nearest plug to the Ring is in the front room and either requires me drilling through a wall or running the cable out through the window and along the wall. Is that safe? How weather proof is the cable? The plug would be indoors but the cable would be exposed to the elements. It's pretty cold, wet and windy round here.