The easiest way to find the latitude / longitude for your Weather station is via services such as Google Maps. They provide highly accurate, but decimal lat / long positions.
These decimals can be easily converted to the degrees minute seconds that WeatherCat uses in its preferences.
However, the digits supplied in WeatherCat do not incorporate the full accuracy of the decimal position.
Thus the location set up in WeatherCat is pretty close, but not as accurate as it could be.
I use WeatherCat with Davis Vanatage Pro in tow locations and love the system. Good job with this software.