I'm a big fan & user of WeatherBug. You can go into Preferences and enable "My Location". A message will pop up informing you that it will use your GPS to determine your location. Best of all, it's free!! You can download it from BlackBerry App World. It WILL ask you for a zip code location when you first install/run the application. I suggest entering your home zip code and then enable GPS location in Preferences.
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