Just finished last week - An android app which automatically downloads a live satellite picture, and using the GPS position of your mobile phone, tells you where you have to go to find the nearest patch of blue sky!

Screenshots

Screenshot_2013-08-30-15-41-20.png
finished.jpg

Internal image processing chain

 The image processing part is written in pure Java SE, so it could theoretically also be included in a servlet and displayed on a regular website.

At the moment however only a satellite image source  for Switzerland is defined, so it will only work here... An extension to other countries would simple require a matching satellite image source, a pre-calulated satellite image without clouds, and the registration of three cities or landmarks in latitude/longitude and correspondent pixel coordinates.

Update

The app is finished and working, but sadly it cannot be published on google play store, due to missing copyright approval of the live satellite image provider. If you want a copy... Well I suppose you could ask me, and I might send you the apk ;)