US weather office (old API), providing 7 days of forecast
MET.no service, worldwide but requires attribution and a subscription to the API users mailing-list.
METAR office, providing current conditions worldwide
no provider, no weather information available
US weather office (new API), providing 7 days of hourly forecast (available since 4.2)
OpenWeatherMap, worldwide and possibly more reliable, but requires attribution and is limited in the number of queries
enable all available providers