Plug-in adapter and Ring Video Doorbell Pro 2

I just had a Ring VIdeo Doorbell 2 installed, but apparently my doorbell transformer is not strong enough (and as of yet can't find it to replace). So I am considering the plug-in adapter. A question on the plug-in adapter and the Doorbell Pro 2: The adapter needs to be plugged in indoors, but how weather resistant is the cable? If I run the cable through a hole in the wall and feed along my exterior siding to the doorbell is that safe? I know the video tutorial mentions running it out a door or window, so I assume it's safe but would like to know for sure.