The app will pull the live temperature for any area in the United States to seed the app when it loads. From there you will see both Fahrenheit and Celsius Temperatures.
Sliders are available so you can see how changing one temperature value affects the other.
This is not intended to be a replacement for your favorite weather app. This is really just about being able to see the relationship between the temperatures scales in real time.
The live weather report is just a bonus. That is simply a live RSS feed. It pulls the feed based on the closest airport. This is a user setting. It is not automatic.