Buienradar NL is a Netherlands weather service which also provides good data on European and global weather. In addition their site has a nice collection of weather photos.
Besides offering apps for Windows, iOS and for mobile phones, they provide free widgets (see the menu item ‘Buienradar op jouw website’ at their page footer) that can easilly be integrated into websites, or can even be used to create your own mini-app by simply creating a local HTML page with the code for the widget in it. For example:
For more information see: