I get that. But wouldnt it be safer and more practical for the device to scrape wx info from some disinterested third party that did not require logging in? Lots of wx sites out there with real time weather conditions.
As long as you require your customer to be part of an unwanted intrusive probe on the residential LAN, I think you will be losing a lions share of your potential audience.
Giving you carte blanche to a local IP that is unprotected by traditional browser security measures is startling to say the least , at least in my humble opinion.
You need to be more transparent about this seemingly minor innocuous step during the installation process. If that detail was in big red bold print (as it should be), you probably would not sell any of these units.