In the WeatherConnect app I click the "set Device Wi-Fi" button and receive the prompt for "Router password" and enter the wi-fi password and it fails. I am not getting to the point where I enter the PWS/Wunderground info.
On the other post - most of my friends have Apple devices. Tonight I will see if my BlueStacks/PC "Android" can run the WeatherConnect app....I will keep you posted.
I'm wondering if you made any progress on this. I have the same unit and the same issue, almost. I was able to get the wifi password to be accepted - make sure you turn off your 5ghz radio in your wifi access point. Then, after you type your password in the app, but before you hit "confirm", hit the plus and minus buttons on top of the C83100's large display for about 3 seconds until the wifi icon starts to flash.
Once you do that, hit "confirm" and a few seconds later "Success!" will appear, but if it does what mine does, it returns you to the main menu.
I'm getting ready to return this to Costco; I had read somewhere that this model did work with the app and that allowed it to connect to WU, but I haven't been able to get it to work.