So we where looking for an alternative and found wunderground.com. Wunderground.com offers a weather api with many functions.
In order to use the module you need an account at wundergrund.com. The basic account is free and allows 500 polls a day. Mod WuWather caches the response-files. So the access limit should be no problem.
You can fully customize the output with the built in CSS-file or your template CSS.
* Make yourself an account at www.wunderground.com
* Generate an API-Key for your application http://www.wunderground.com/weather/api
* Download and install the "wuweather Module" with the Joomla installation manager
* Create a new "wuWeather Module"
* Set the key, weather-location (Country, Town) and other in module-configuration
* Fixed installation for Joomla 3.x