Alfie is using common WordPress functions in order to make its content translatable. It will look inside /lang folder for any translation file available and apply that translation according to the locale variable defined by the plugin used for translation. So, for both qTranslate and WPML, Alfie WP Weather will always show the translation, if available, based on the language selected by the user.
In order to make the content available for translation in a language not shipped with the plugin, you should open default.po with Poedit and save it with the right name ( i.e. for german you should save the file as alfie_wp_weather-de_DE.po ), make the necessary translations and hit save. When you do this, in the /lang directory will appear a file named alfie_wp_weather-de_DE.mo. That's your german translation. So, following these steps should give you a localized version of the plugin.
Important: Make sure that in Poedit/Catalog/Properties/Language when editing alfie_wp_weather-de_DE.po you change the default en_US to de_DE and so on, according to the language you're translating to.
If you encounter issues, drop us a line here :)
The Alfie Team