X-Air is correct, this post is better placed in the iOS Client forum at
http://athena.trixology.com/index.php?board=10.0. However, he is not correct about the app being local only. (Don't worry, he is happy to be right 50% of the time because that improves his average
.) Internet 1 and Internet 2 are where you set either the IP address on your home network that you have established for remote connections back to your home network from outside your network or the dyndns proxy name you have established for the same purpose.
You need to setup port forwarding for WeatherCat in your router in order for the iOS apps to connect remotely. The default URLs in Internet 1 and 2 are there for you to test your router settings. When your router settings are correctly fixed, you will be able to pull up the test data in the app using the default URL. Once that is working, change the setting in Internet 1 to your correct address for port forwarding to allow you to see your own WeatherCat data. Internet 2 simply allows you to either keep the test data as an option, or, in the event that you have two installations of WeatherCat on different networks (one at home and one on a remote island in the South Pacific), you can retain the settings for both.
You can read about how to do all this in the WeatherCat Wiki:
http://wiki.trixology.com/index.php/WeatherCat_Clients