Searching for or downloading files with this naming convention poses significant risks:

The German word for "phonebook." There is no official connection between the Weather Now app and any German directory service.

The file format used for iOS applications. Official apps are downloaded directly from the Apple App Store. Safety and Security Risks

Trusted alternatives include AccuWeather, The Weather Channel, and WeatherBug. WeatherBug: Weather Forecast - App Store - Apple

Sites hosting such specific "IPA" filenames often bundle them with malware or adware that can compromise your device.