Attached you find a Domino database which fetch weather data (using json) from the swedish weather institute SMHI using a Java Agent.
You need to specify the latitude and longitude cordinates in the agent.
Image below show the collected data by date and time, for 11 day forecast, all the available parameters are included
All you have to do now is to create an xpage and display a "sun image" on the web if there are no clouds ;-)
Note: SMHI is for Swedish weather only, if you want weather for another part of the world you need to find another json api and modify the agent accordingly.
Click below to download